Introduce feature flag for OOP-R canvas

This CL simply sets up the finch flag for OOP-R canvas.
This flag flips the bits required for OOP-R when creating the context.

Bug: 1023277
Change-Id: Ic5da502ba1eaf8c01a308d1f88ec17a07e31f625
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2036521Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Khushal <khushalsagar@chromium.org>
Commit-Queue: Jonah Chin <jochin@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#738691}

content/public/common/content_features.cc

@@ -126,6 +126,10 @@ const base::Feature kCanvas2DImageChromium {
 #endif
 };
 
+// Enables the use of out of process rasterization for canvas.
+const base::Feature kCanvasOopRasterization{"CanvasOopRasterization",
+                                            base::FEATURE_DISABLED_BY_DEFAULT};
+
 // When enabled, event.movement is calculated in blink instead of in browser.
 const base::Feature kConsolidatedMovementXY{"ConsolidatedMovementXY",
                                             base::FEATURE_ENABLED_BY_DEFAULT};

content/public/common/content_features.h

@@ -37,6 +37,7 @@ CONTENT_EXPORT extern const base::Feature kCacheStorageParallelOps;
 CONTENT_EXPORT extern const base::Feature kCacheStorageEagerReading;
 CONTENT_EXPORT extern const base::Feature kCacheStorageHighPriorityMatch;
 CONTENT_EXPORT extern const base::Feature kCanvas2DImageChromium;
+CONTENT_EXPORT extern const base::Feature kCanvasOopRasterization;
 CONTENT_EXPORT extern const base::Feature kConsolidatedMovementXY;
 CONTENT_EXPORT extern const base::Feature kConversionMeasurement;
 CONTENT_EXPORT extern const base::Feature kCookieDeprecationMessages;

content/renderer/render_thread_impl.cc

@@ -1228,10 +1228,11 @@ RenderThreadImpl::SharedMainThreadContextProvider() {
   }
 
   bool support_locking = false;
-  bool support_gles2_interface = true;
   bool support_raster_interface = true;
-  bool support_oop_rasterization = false;
-  bool support_grcontext = true;
+  bool support_oop_rasterization =
+      base::FeatureList::IsEnabled(features::kCanvasOopRasterization);
+  bool support_gles2_interface = !support_oop_rasterization;
+  bool support_grcontext = !support_oop_rasterization;
   // Enable automatic flushes to improve canvas throughput.
   // See https://crbug.com/880901
   bool automatic_flushes = true;