Remove PPAPISharedImagesSwapChainAllowed and feature flags

The feature was enabled by default in M112 and according to our launch
timelines we're removing code after M114 branched.

This CL removes command line switch, feature flag and escape hatch
policy (with corresponding preferences).

Follow-up CLs will simplify and remove more code once M115 branched.

Bug: 1410109
Change-Id: I61a8e32284b4f7056ae73b186bdb7ad9c492cc69
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4521684
Reviewed-by: Derek Schuff <[email protected]>
Reviewed-by: Ken Buchanan <[email protected]>
Reviewed-by: Avi Drissman <[email protected]>
Reviewed-by: Brendon Tiszka <[email protected]>
Commit-Queue: Vasiliy Telezhnikov <[email protected]>
Reviewed-by: Owen Min <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1143576}
diff --git a/ppapi/proxy/ppb_graphics_3d_proxy.h b/ppapi/proxy/ppb_graphics_3d_proxy.h
index 8543a45f..5cba0779 100644
--- a/ppapi/proxy/ppb_graphics_3d_proxy.h
+++ b/ppapi/proxy/ppb_graphics_3d_proxy.h
@@ -36,10 +36,7 @@
 
 class PPAPI_PROXY_EXPORT Graphics3D : public PPB_Graphics3D_Shared {
  public:
-  Graphics3D(const HostResource& resource,
-             const gfx::Size& size,
-             const bool single_buffer,
-             bool use_shared_images_swapchain);
+  Graphics3D(const HostResource& resource, const gfx::Size& size);
 
   Graphics3D(const Graphics3D&) = delete;
   Graphics3D& operator=(const Graphics3D&) = delete;
@@ -64,7 +61,6 @@
       int32_t start,
       int32_t end) override;
   void EnsureWorkVisible() override;
-  void TakeFrontBuffer() override;
   void ResolveAndDetachFramebuffer() override;
 
  private:
@@ -76,9 +72,6 @@
   void DoResize(gfx::Size size) override;
 
   std::unique_ptr<PpapiCommandBufferProxy> command_buffer_;
-
-  uint64_t swap_id_ = 0;
-  bool single_buffer = false;
 };
 
 class PPB_Graphics3D_Proxy : public InterfaceProxy {
@@ -130,7 +123,6 @@
   void OnMsgSwapBuffers(const HostResource& context,
                         const gpu::SyncToken& sync_token,
                         const gfx::Size& size);
-  void OnMsgTakeFrontBuffer(const HostResource& context);
   void OnMsgEnsureWorkVisible(const HostResource& context);
   void OnMsgResolveAndDetachFramebuffer(const HostResource& context);
   void OnMsgResize(const HostResource& context, gfx::Size size);