Bug 1154322 - Always use DrawTargetCG when painting directly into a window on OS X (unaccelerated drawRect rendering). r=jrmuizel

This also gets rid of the code path that allowed us to test DrawTargetCairo for OS X content rendering. As far as I know, nobody has made use of it in the past 12 months.

This change makes us not crash if SupportsAzureContentForType(BackendType::COREGRAPHICS) returns false, which will be the case if you flip the azure content pref to a supported non-"cg" value.

widget/cocoa/nsChildView.mm

@@ -3443,29 +3443,13 @@ NSEvent* gLastDragMouseDownEvent = nil;
   // Create Cairo objects.
   nsRefPtr<gfxQuartzSurface> targetSurface;
 
-  nsRefPtr<gfxContext> targetContext;
-  if (gfxPlatform::GetPlatform()->SupportsAzureContentForType(gfx::BackendType::COREGRAPHICS)) {
-    RefPtr<gfx::DrawTarget> dt =
-      gfx::Factory::CreateDrawTargetForCairoCGContext(aContext,
-                                                      gfx::IntSize(backingSize.width,
-                                                                   backingSize.height));
-    MOZ_ASSERT(dt); // see implementation
-    dt->AddUserData(&gfxContext::sDontUseAsSourceKey, dt, nullptr);
-    targetContext = new gfxContext(dt);
-  } else if (gfxPlatform::GetPlatform()->SupportsAzureContentForType(gfx::BackendType::CAIRO)) {
-    // This is dead code unless you mess with prefs, but keep it around for
-    // debugging.
-    targetSurface = new gfxQuartzSurface(aContext, backingSize);
-    targetSurface->SetAllowUseAsSource(false);
-    RefPtr<gfx::DrawTarget> dt =
-      gfxPlatform::GetPlatform()->CreateDrawTargetForSurface(targetSurface,
-                                                             gfx::IntSize(backingSize.width,
-                                                                          backingSize.height));
-    dt->AddUserData(&gfxContext::sDontUseAsSourceKey, dt, nullptr);
-    targetContext = new gfxContext(dt);
-  } else {
-    MOZ_ASSERT_UNREACHABLE("COREGRAPHICS is the only supported backed");
-  }
+  RefPtr<gfx::DrawTarget> dt =
+    gfx::Factory::CreateDrawTargetForCairoCGContext(aContext,
+                                                    gfx::IntSize(backingSize.width,
+                                                                 backingSize.height));
+  MOZ_ASSERT(dt); // see implementation
+  dt->AddUserData(&gfxContext::sDontUseAsSourceKey, dt, nullptr);
+  nsRefPtr<gfxContext> targetContext = new gfxContext(dt);
 
   // Set up the clip region.
   nsIntRegionRectIterator iter(region);