Force more GL state into a known state

DirectContextProvider shares a GL context with SkiaRenderer. Both of
these have GL state trackers that don't know anything about each other.
ScopedUseContextProvider is responsible for keeping the state trackers
consistent.

These changes were necessary to make my reuse of GLRenderer color
conversion work. I believe that GLRendererCopier has similar
requirements, but that we got lucky with timing and bugs did not
manifest.

Change-Id: I9ac64f51498df0518aeac296ef2bea8fd156d635
Reviewed-on: https://chromium-review.googlesource.com/c/1495196Reviewed-by: Peng Huang <penghuang@chromium.org>
Commit-Queue: Jonathan Backer <backer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636606}

components/viz/service/display_embedder/direct_context_provider.cc

@@ -140,10 +140,12 @@ void DirectContextProvider::SetGLRendererCopierRequiredState(
   // Get into known state (see
   // SkiaOutputSurfaceImplOnGpu::ScopedUseContextProvider).
   gles2_implementation_->BindFramebuffer(GL_FRAMEBUFFER, 0);
-  gles2_implementation_->Disable(GL_SCISSOR_TEST);
-  gles2_implementation_->Disable(GL_STENCIL_TEST);
-  gles2_implementation_->Disable(GL_BLEND);
-  gles2_implementation_->ActiveTexture(GL_TEXTURE0);
+
+  decoder_->RestoreActiveTexture();
+  decoder_->RestoreProgramBindings();
+  decoder_->RestoreAllAttributes();
+  decoder_->RestoreGlobalState();
+  decoder_->RestoreBufferBindings();
 
   if (texture_client_id) {
     if (!framebuffer_id_)

components/viz/service/display_embedder/skia_output_surface_impl_on_gpu.cc

@@ -82,10 +82,6 @@ class SkiaOutputSurfaceImplOnGpu::ScopedUseContextProvider {
     // side consistent with that.
     auto* api = impl_on_gpu_->api_;
     api->glBindFramebufferEXTFn(GL_FRAMEBUFFER, 0);
-    api->glDisableFn(GL_SCISSOR_TEST);
-    api->glDisableFn(GL_STENCIL_TEST);
-    api->glDisableFn(GL_BLEND);
-    api->glActiveTextureFn(GL_TEXTURE0);
     impl_on_gpu_->context_provider_->SetGLRendererCopierRequiredState(
         texture_client_id);
   }