gpu: Disallow zero sized offscreen framebuffers

content/common/gpu/gpu_command_buffer_stub.cc

Index: content/common/gpu/gpu_command_buffer_stub.cc
diff --git a/content/common/gpu/gpu_command_buffer_stub.cc b/content/common/gpu/gpu_command_buffer_stub.cc
index e14cf986092b9c8817dcd3024e2474890734c368..29ad1da9a4b17615d5d98da9821ab44cf5d9d9ce 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -201,6 +201,14 @@ GpuCommandBufferStub::GpuCommandBufferStub(
 
   use_virtualized_gl_context_ |=
       context_group_->feature_info()->workarounds().use_virtualized_gl_contexts;
+
+  bool is_offscreen = surface_id_ == 0;
+  if (is_offscreen && initial_size_.IsEmpty()) {

[hendrikw, 2015/04/24 18:33:38]

I might rename initial_size_ to initial_offscreen_size_ later, it's a bit
misleading as it.

+    // If we're an offscreen surface with zero width and/or height, set to a
+    // non-zero size so that we have a complete framebuffer for operations like
+    // glClear.
+    initial_size_ = gfx::Size(1, 1);
+  }
 }
 
 GpuCommandBufferStub::~GpuCommandBufferStub() {