[WebGL-chromium] Return meaningful information in WebGL context creation error message

content/renderer/renderer_blink_platform_impl.cc

Index: content/renderer/renderer_blink_platform_impl.cc
diff --git a/content/renderer/renderer_blink_platform_impl.cc b/content/renderer/renderer_blink_platform_impl.cc
index 242a5950a3c6cca3b1b844a75efd806d3955dfcf..e477905ad6c846cef7b4a9c4abed9cec348424ec 100644
--- a/content/renderer/renderer_blink_platform_impl.cc
+++ b/content/renderer/renderer_blink_platform_impl.cc
@@ -929,7 +929,31 @@ bool RendererBlinkPlatformImpl::processMemorySizesInBytes(
 blink::WebGraphicsContext3D*
 RendererBlinkPlatformImpl::createOffscreenGraphicsContext3D(
     const blink::WebGraphicsContext3D::Attributes& attributes) {
-  return createOffscreenGraphicsContext3D(attributes, NULL);
+  blink::WebGLInfo gl_info;

[piman, 2014/10/27 19:43:47]

Why create a WebGLInfo if we're going to discard it?

[sivag, 2014/10/28 15:29:00]

Done. Sorry i missed this.

+  return createOffscreenGraphicsContext3D(attributes, NULL, &gl_info);
+}
+
+blink::WebGraphicsContext3D*
+RendererBlinkPlatformImpl::createOffscreenGraphicsContext3D(
+    const blink::WebGraphicsContext3D::Attributes& attributes,
+    blink::WebGraphicsContext3D* share_context,
+    blink::WebGLInfo* gl_info) {
+
+  RenderThreadImpl* render_thread = RenderThreadImpl::current();
+  if (render_thread && gl_info) {
+    GpuChannelHost* gpu_channel_host = render_thread->GetGpuChannel();

[piman, 2014/10/27 19:43:47]

This could be NULL, or a different channel than the one that was created/used
when creating the context (l.979), e.g. on the first creation or after a GPU
process loss. It could lead to inconsistent data.

How about: moving this code after l.981 in the other overload (passing gl_info
to that one and making this one a trivial wrapper).

[sivag, 2014/10/28 15:29:00]

Done.

+    if (gpu_channel_host) {
+      const gpu::GPUInfo& gpu_info = gpu_channel_host->gpu_info();
+      gl_info->vendorInfo.assign(
+          blink::WebString::fromUTF8(gpu_info.gl_vendor));
+      gl_info->rendererInfo.assign(
+          blink::WebString::fromUTF8(gpu_info.gl_renderer));
+      gl_info->driverVersion.assign(
+          blink::WebString::fromUTF8(gpu_info.gl_version));
+    }
+  }
+
+  return createOffscreenGraphicsContext3D(attributes, share_context);
 }
 
 blink::WebGraphicsContext3D*