Enable RGBA_4444 in GpuRasterBufferProvider

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index e7d309db8a964fa061bd76ef29ba3d21fcd78886..9d06c6d7449e910f454999d83b488e20787b1a22 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -486,7 +486,7 @@ ResourceProvider::~ResourceProvider() {
   gl->Finish();
 }
 
-bool ResourceProvider::IsResourceFormatSupported(ResourceFormat format) const {
+bool ResourceProvider::IsTextureFormatSupported(ResourceFormat format) const {
   gpu::Capabilities caps;
   if (compositor_context_provider_)
     caps = compositor_context_provider_->ContextCapabilities();
@@ -505,13 +505,41 @@ bool ResourceProvider::IsResourceFormatSupported(ResourceFormat format) const {
     case RED_8:
       return caps.texture_rg;
     case LUMINANCE_F16:
+    case RGBA_F16:
       return caps.texture_half_float_linear;
+  }
+
+  NOTREACHED();
+  return false;
+}
+
+bool ResourceProvider::IsRenderBufferFormatSupported(
+    ResourceFormat format) const {
+  gpu::Capabilities caps;
+  if (compositor_context_provider_)
+    caps = compositor_context_provider_->ContextCapabilities();
+
+  switch (format) {
+    case RGBA_4444:
+    case RGBA_8888:
+    case RGB_565:
+      return true;
+    case BGRA_8888:
+      return caps.render_buffer_format_bgra8888;
     case RGBA_F16:
       // TODO(ccameron): This will always return false on pixel tests, which
       // makes it un-test-able until we upgrade Mesa.
       // https://crbug.com/687720
       return caps.texture_half_float_linear &&
              caps.color_buffer_half_float_rgba;
+    case LUMINANCE_8:
+    case ALPHA_8:
+    case RED_8:
+    case ETC1:
+    case LUMINANCE_F16:
+      // We don't currently render into these formats. If we need to render into
+      // these eventually, we should expand this logic.
+      return false;
   }
 
   NOTREACHED();