import changes from `dev' branch of rmottola/Arctic-Fox:

- import from mozilla: Bug 1208969 TSFTextStore shouldn't grant document lock after starting to destroy the context r=emk (5766724701d5) (387b995959)
- import from mozilla: Bug 1096804 - Add a new asynchronous callback interface for Windows taskbar thumbnail and preview image requests. r=roc (8afe4f072efd) (2b5114dbf3)
- Bug 890156 - patch 0.1 - Switch from 'display pixels' to 'desktop pixels' terminology in widget code. r=kats (a5bd32715a)
- Bug 890156 - patch 0.3 - Create a version of nsIWidget::Create that takes Desktop pixels, because that's what we actually need to pass in some cases. r=mstange (ca85c82533)
- Bug 890156 - patch 1 - Add nsIWidget::GetDesktopToDeviceScale() method. r=emk (40a608fccd)
- Bug 1189622 part 1 - Ensure the in-fullscreen-change flag is set before calling the second phase. r=smaug (52b8f80f37)
- Bug 1189622 part 2 - Allow widget's MakeFullScreen to fail, and call FinishFullscreenChange directly if that happens. r=smaug (b9a89868b3)
- Bug 1189622 part 3 - Return failure if fullscreen support is not available for the X11 desktop. r=karlt (8845780b0f)
- Bug 890156 - patch 0.0 - Declare a DesktopPixel type in Units.h, to be used for the coordinate system used by the host system to manage the desktop space. r=kats (230fcc152e)
- Bug 890156 - patch 2 - Expose DevicePixelsPerDesktopPixel through nsIBaseWindow and its implementations. r=emk (255b157d4f)
- Bug 1096804 - Update taskbar thumbnail and preview handler code to support an asynchronous response that receives a canvas from front end js. Deprecate old sync apis. r=roc (c9bdb6a318)
- Bug 1096804 - Fix debug build error, remove use of non-existent HRESULT and assert. r=buildfix (bfc82b5eb5)
- Bug 890156 - patch 3 - Remove gfxWindowsPlatform::GetDPIScale and replace it with methods in WinUtils, ready for per-monitor DPI support. r=emk (e72d779b32)
- Bug 1234422 TSFTextStore should retry to notify TSF/TIP of layout change if synchronous calls of OnLayoutChange() don't cause retrieving layout information r=m_kato (ea7dd1ccd3)
- Bug 1222190 - Implement GetTimeAsyncForPossibleBackwardsSkew for windows to fix backwards skew on hibernation. r=birtles (4cb42d1cda)
- Bug 506815 - Replace MouseTrailer with TrackMouseEvent. r=jimm (454cd15037)
- Bug 1232669 - Fixed typo MOOUSEMOVE in nsWindow r=chutten (cf70097af6)
- Bug 1235821 - Don't track mouseleave when capturing mouse. r=jimm (5a7bbf1d62)
- Bug 1222444 - remove unused variable in nsWindow::GetMessageTimeStamp r=roc (d45f63dd0e)
- Bug 1217565 - Fix assertion in nsWindow::IPCWindowProcHandler to account for suppressed neutering; r=jimm (d27f977c9c)
- Bug 1234838 - Update the windows backwards time skew fix code to use a PostMessage rather than a gecko NS_DispatchToMainThread. r=karlt (74c3d7b3b9)
- Bug 1191583 - Add telemetry probes for touch usage. r=jimm p=ally (7e00f1bb9e)
- Bug 1165303 - avoid hiding and reshowing the window in response to our own settext messages because it makes Windows 10 unhappy, r=jimm (4190d342a8)
- Bug 890156 - patch 4 - Update widget/windows code for per-monitor DPI support. r=emk (76193d54eb)
- put back some XP vs Vista stuff (fba145ee7a)
- Bug 1205643 - "Wrong scrollbar border prevents scrolling to cursor when mouse is on the screen edge". r=karlt (206ad88949)
- Bug 890156 - patch 5 - Make Windows native-theme code handle per-monitor DPI scaling when necessary. r=emk (dad68a3767)
- Bug 890156 - patch 6 - Update window placement code to work with desktop pixels, for per-monitor DPI support on Windows. r=emk (1e9adc0a84)
- Bug 890156 - patch 7 - Declare that we support Windows per-monitor DPI via the app manifest. r=emk (98856d7a17)
- Bug 890156 - patch 8 - Explicitly set line-height in the About dialog, to avoid discrepancies in spacing across screens with different DPI. r=emk (ce8430ea77)
- Bug 1239589 - Change nsBaseWidget::mBounds to a LayoutDeviceIntRect. r=kats. (69ddcf93b0)
- Bug 1239864 (part 1) - Add new, nicer rect-iterators for nsRegion and nsIntRegion. r=roc. (0a7af16ebb)
- Bug 1239864 (part 2) - Use the new rect iterators in nsRegion.cpp. r=roc. (c7413ab413)
- Bug 1239864 (part 3) - Use the new rect iterators in docshell/ and dom/. r=baku. (34d65b2989)
- Bug 1236266 - Use release assert in IPC serialization for regions (r=jmuizelaar) (418442b5fe)
- Bug 1219352 - Rearrange fields in FrameMetrics. r=botond (60fab5aec3)
- Bug 1219352 - Pack the FrameMetrics booleans. r=botond (8b29ce6ca4)
- Bug 1193055 - Only fire TransformBegin/TransformEnd notifications for actual wheel animations. r=botond (20cf23f07f)
- Bug 1193055 - Update windowed plugin visibility in response to apz scroll in the chrome process vs. relying on a full round trip through content. Reduces lag in windowed plugin updates. r=kats (5387bc8841)
- Bug 1193055 - Follow up, remove extraneous methods noted in review comments. r=followup (3a989b6f68)
- Bug 1226826 - Add a CheckerboardEvent class to record stuff when checkerboarding happens. r=botond (a82ac77b4b)
- Bug 1239385 - Use correct coordinate system when computing the amount to scroll during a pinch r=botond (c0e8bec574)
- Bug 1219352 - Update a couple of bool-setters to take a bool argument. r=botond (9efebb15fd)
- Bug 1226826 - Record velocity at point of displayport request in checkerboard event. r=botond (8e496ccc94)
- Bug 1194851 - Add helper functions HasDisplayPort() and HasCriticalDisplayPort(). r=kats (a0da8cd2a1)
- Bug 1229039 - Miscellaneous logging fixes/updates. r=botond (c055e26989)
- Bug 1228597 - Clean up code paths that (un)apply a pres shell resolution. r=tn,botond (683f43d0a8)
- Bug 1232852 (part 9) - Simplify ReleasePointerCaptureCaller. r=tn. (67b0f86278)
- Bug 1229752 - When C++ APZ scroll offset diverges from the Gecko scroll offset, it is not being applied properly to the event position r=botond,tnikkel (f63f0405a9)
- Bug 1226826 - Record paint times in the checkerboard event. r=botond (47f92a1d8d)
- Bug 1239864 (part 4) - Use the new rect iterators in gfx/. r=nical. (4189b5929d)
- Bug 1239864 (part 5) - Use the new rect iterators in gfx/. r=nical. (92b4c72e5f)
- Bug 1232484 - Remove 'using namespace gfx' and missing includes that were papered over by unified builds but can cause breakage. r=BenWa (40f70a6ca1)
- Bug 1239864 (part 6) - Use the new rect iterators in gfx/. r=nical. (f6ececa928)
- Bug 1239864 (part 7) - Use the new rect iterators in gfx/. r=nical. (4bcdc8fbc1)
- Bug 1231888 - Remove AutoCairoPixmanBugWorkaround. r=jrmuizel. (64ad72f140)
- Bug 1238438 (part 1) - Remove dead function gfxUtils::PathFromRegion(). r=nical. (84c95c7f35)
- Bug 1238438 (part 2) - Inline both ClipToRegionInternal() functions.  r=nical. (14276bddb8)
- Bug 1238438 (part 3) - Inline both PathFromRegionInternal() functions. r=nical. (84f9636b9c)
- Bug 1239864 (part 8) - Use the new rect iterators in gfx/. r=nical. (6250fcd573)

docshell/base/nsDocShell.cpp

@@ -5747,6 +5747,23 @@ nsDocShell::GetUnscaledDevicePixelsPerCSSPixel(double* aScale)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDocShell::GetDevicePixelsPerDesktopPixel(double* aScale)
+{
+  if (mParentWidget) {
+    *aScale = mParentWidget->GetDesktopToDeviceScale().scale;
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIBaseWindow> ownerWindow(do_QueryInterface(mTreeOwner));
+  if (ownerWindow) {
+    return ownerWindow->GetDevicePixelsPerDesktopPixel(aScale);
+  }
+
+  *aScale = 1.0;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDocShell::SetPosition(int32_t aX, int32_t aY)
 {