aura: fix fullscreen pepper flash

content/renderer/render_widget_fullscreen_pepper.cc

Index: content/renderer/render_widget_fullscreen_pepper.cc
diff --git a/content/renderer/render_widget_fullscreen_pepper.cc b/content/renderer/render_widget_fullscreen_pepper.cc
index ce90c309f257c2938d87a85c2e620f470586e4f7..01f9c8b043b5a0cd3683fcdd8aa7d26737575a82 100644
--- a/content/renderer/render_widget_fullscreen_pepper.cc
+++ b/content/renderer/render_widget_fullscreen_pepper.cc
@@ -424,6 +424,9 @@ const float kTexCoords[] = {
 
 bool RenderWidgetFullscreenPepper::InitContext() {
   gpu::gles2::GLES2Implementation* gl = context_->GetImplementation();
+  gl->ResizeCHROMIUM(size().width(), size().height());
+  gl->Viewport(0, 0, size().width(), size().height());
+
   program_ = gl->CreateProgram();
 
   GLuint vertex_shader =