Set up Finch experiment for expanded GPU rasterization trigger

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 7257b007bca385082e9e507b6c4678334854ab50..87c62c06a7bd34b658cab12ba2c702394d60191e 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -20,6 +20,7 @@
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/process/kill.h"
@@ -472,6 +473,11 @@ static bool ShouldUseAcceleratedFixedRootBackground(float device_scale_factor) {
   return DeviceScaleEnsuresTextQuality(device_scale_factor);
 }
 
+static bool ShouldUseExpandedHeuristicsForGpuRasterization() {
+  return base::FieldTrialList::FindFullName(
+             "GpuRasterizationExpandedContentWhitelist") == "Enabled";
+}
+
 static FaviconURL::IconType ToFaviconType(blink::WebIconURL::Type type) {
   switch (type) {
     case blink::WebIconURL::TypeFavicon:
@@ -751,6 +757,8 @@ void RenderViewImpl::Initialize(RenderViewImplParams* params) {
       ShouldUseAcceleratedFixedRootBackground(device_scale_factor_));
   webview()->settings()->setCompositedScrollingForFramesEnabled(
       ShouldUseCompositedScrollingForFrames(device_scale_factor_));
+  webview()->settings()->setUseExpandedHeuristicsForGpuRasterization(
+      ShouldUseExpandedHeuristicsForGpuRasterization());
 
   ApplyWebPreferences(webkit_preferences_, webview());