Define a --force-gpu-rasterization flag

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index f491f8b273bc19c0411b13698a0a9e323df03a17..37e8a9b27c3cb9e97c03396a8cda99c83061372d 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -115,6 +115,7 @@
 #include "ui/base/ui_base_switches.h"
 #include "v8/include/v8.h"
 #include "webkit/renderer/compositor_bindings/web_external_bitmap_impl.h"
+#include "webkit/renderer/compositor_bindings/web_layer_impl.h"
 
 #if defined(OS_ANDROID)
 #include <cpu-features.h>
@@ -391,6 +392,41 @@ void RenderThreadImpl::Init() {
   if (command_line.HasSwitch(cc::switches::kEnableGpuBenchmarking))
       RegisterExtension(GpuBenchmarkingExtension::Get());
 
+  is_impl_side_painting_enabled_ =
+      command_line.HasSwitch(switches::kEnableImplSidePainting) &&
+      !command_line.HasSwitch(switches::kDisableImplSidePainting);

[boliu, 2014/03/10 15:40:38]

impl_side_painting was enabled on android if no switch is defined, does this
reverse the default on android?

[ajuma, 2014/03/10 15:53:56]

The Android default is now handled in IsImplSidePaintingEnabled() in
content/browser/gpu/compositor_util.cc, which causes kEnableImplSidePainting to
get added to the renderer command line in AppendGpuCommandLineFlags() in
content/browser/renderer_host/render_process_host_impl.cc. So by the time the
renderer performs the check here, the switch should be defined.

[ajuma, 2014/03/10 15:59:35]

Actually, this code path will only get followed for out-of-process renderers. Do
we use in-process renderers anywhere on Android (e.g. for webview)?

+  webkit::WebLayerImpl::SetImplSidePaintingEnabled(
+      is_impl_side_painting_enabled_);
+
+  is_map_image_enabled_ =
+      command_line.HasSwitch(switches::kEnableMapImage) &&
+      !command_line.HasSwitch(switches::kDisableMapImage);
+
+  if (command_line.HasSwitch(switches::kDisableLCDText)) {
+    is_lcd_text_enabled_ = false;
+  } else if (command_line.HasSwitch(switches::kEnableLCDText)) {
+    is_lcd_text_enabled_ = true;
+  } else {
+#if defined(OS_ANDROID)
+    is_lcd_text_enabled_ = false;
+#else
+    is_lcd_text_enabled_ = true;
+#endif
+  }
+
+  is_gpu_rasterization_enabled_ = false;
+  is_gpu_rasterization_forced_ = false;
+  if (is_impl_side_painting_enabled_ &&
+      !command_line.HasSwitch(switches::kDisableGpuRasterization)) {
+    if (command_line.HasSwitch(switches::kForceGpuRasterization)) {
+      is_gpu_rasterization_forced_ = true;
+    } else if (command_line.HasSwitch(switches::kEnableGpuRasterization) ||
+               command_line.HasSwitch(
+                   switches::kEnableBleedingEdgeRenderingFastPaths)) {
+      is_gpu_rasterization_enabled_ = true;
+    }
+  }
+
   // Note that under Linux, the media library will normally already have
   // been initialized by the Zygote before this instance became a Renderer.
   base::FilePath media_path;
@@ -738,7 +774,7 @@ void RenderThreadImpl::EnsureWebKitInitialized() {
 #if !defined(OS_ANDROID)
   use_skia_scaled_image_cache =
       command_line.HasSwitch(switches::kEnableDeferredImageDecoding) ||
-      cc::switches::IsImplSidePaintingEnabled();
+      is_impl_side_painting_enabled_;
 #endif
   if (!use_skia_scaled_image_cache)
     SkGraphics::SetImageCacheByteLimit(0u);