During image destroy, delete textures only if we have a GL context.

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 189215122af0bff2aeb71e88d7364c1a7ad0fe21..4847218e2199d493ee9fe6cf74a12e7653896e57 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -946,7 +946,8 @@ void GpuCommandBufferStub::OnRegisterGpuMemoryBuffer(
   if (decoder_) {
     gpu::gles2::ImageManager* image_manager = decoder_->GetImageManager();
     DCHECK(image_manager);
-    image_manager->AddImage(image.get(), id);
+    if (!image_manager->AddImage(image.get(), id))
+      return;
   }
 }
 
@@ -956,7 +957,8 @@ void GpuCommandBufferStub::OnDestroyGpuMemoryBuffer(int32 id) {
   if (decoder_) {
     gpu::gles2::ImageManager* image_manager = decoder_->GetImageManager();
     DCHECK(image_manager);
-    image_manager->RemoveImage(id);
+    if (!image_manager->RemoveImage(id))
+      return;
   }
 }