CC: Plumb LayerSettings parameter for cc::Layer construction.

android_webview/browser/hardware_renderer.cc

Index: android_webview/browser/hardware_renderer.cc
diff --git a/android_webview/browser/hardware_renderer.cc b/android_webview/browser/hardware_renderer.cc
index 8ee14f50318c09abe333db5e58ea8354aa6beb6c..caa7e2c34d90367e3708facb7fd4a047005b8097 100644
--- a/android_webview/browser/hardware_renderer.cc
+++ b/android_webview/browser/hardware_renderer.cc
@@ -13,6 +13,7 @@
 #include "android_webview/browser/shared_renderer_state.h"
 #include "android_webview/public/browser/draw_gl.h"
 #include "base/auto_reset.h"
+#include "base/lazy_instance.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/layers/delegated_frame_provider.h"
@@ -33,13 +34,16 @@
 
 namespace android_webview {
 
+base::LazyInstance<cc::LayerSettings> g_layer_settings =
+    LAZY_INSTANCE_INITIALIZER;

[boliu, 2015/05/20 15:51:02]

Lazy instance feels over kill here. I don't think constructing a LayerSettings
is expensive?

And should use a function if the purpose is to unify LayerSettings creation,
since lazy instance doesn't have the opportunity to change any of the settings
from default.

[loyso (OOO), 2015/05/21 05:12:35]

Yes, thread-safety is over kill here. Our style guide says: "Static or global
variables of class type are forbidden". It allows only structs of POD (which is
better to be updated in C++11 trivial/non-trivial terms). I could replace lazy
instances with simple static functions everywhere.

Linters are ok with "cc::LayerSettings g_layer_settings" except that I need to
remove the empty destructor.

What do you think?

[boliu, 2015/05/21 05:23:32]

That's definitely not allowed. Having the constructor means it creates a static
initializer. And not having a constructor means the members are not initialized.
Either just create LayerSettings on the stack where it's needed. Or create a
global function, in an anonymous namespace, that constructs and returns a *copy*
of LayerSettings.

No threading issues if you never have a global instance.

+
 HardwareRenderer::HardwareRenderer(SharedRendererState* state)
     : shared_renderer_state_(state),
       last_egl_context_(eglGetCurrentContext()),
       stencil_enabled_(false),
       viewport_clip_valid_for_dcheck_(false),
       gl_surface_(new AwGLSurface),
-      root_layer_(cc::Layer::Create()),
+      root_layer_(cc::Layer::Create(g_layer_settings.Get())),
       resource_collection_(new cc::DelegatedFrameResourceCollection),
       output_surface_(NULL) {
   DCHECK(last_egl_context_);
@@ -134,7 +138,8 @@ void HardwareRenderer::CommitFrame() {
     frame_provider_ = new cc::DelegatedFrameProvider(
         resource_collection_.get(), frame->delegated_frame_data.Pass());
 
-    delegated_layer_ = cc::DelegatedRendererLayer::Create(frame_provider_);
+    delegated_layer_ = cc::DelegatedRendererLayer::Create(
+        g_layer_settings.Get(), frame_provider_);
     delegated_layer_->SetBounds(frame_size_);
     delegated_layer_->SetIsDrawable(true);