[PPAPI] Fix the CommitLayers() will never be completed issue

content/renderer/pepper/pepper_compositor_host.cc

Index: content/renderer/pepper/pepper_compositor_host.cc
diff --git a/content/renderer/pepper/pepper_compositor_host.cc b/content/renderer/pepper/pepper_compositor_host.cc
index 47c0fccfe6cb06198183de4377c305c91e2c0e9c..baba5b89b16ee0d272f15ec4002b0d9be4860e49 100644
--- a/content/renderer/pepper/pepper_compositor_host.cc
+++ b/content/renderer/pepper/pepper_compositor_host.cc
@@ -10,6 +10,7 @@
 #include "cc/layers/solid_color_layer.h"
 #include "cc/layers/texture_layer.h"
 #include "cc/resources/texture_mailbox.h"
+#include "cc/trees/layer_tree_host.h"
 #include "content/public/renderer/renderer_ppapi_host.h"
 #include "content/renderer/pepper/gfx_conversion.h"
 #include "content/renderer/pepper/host_globals.h"
@@ -366,6 +367,12 @@ int32_t PepperCompositorHost::OnHostMsgCommitLayers(
       layers_.push_back(LayerData(cc_layer, *pp_layer));
   }
 
+  // We need to force a commit for each CommitLayers() call, even if no layers
+  // changed since the last call to CommitLayers(). This is so
+  // WiewInitiatedPaint() will always be called.
+  if (layer_->layer_tree_host())
+    layer_->layer_tree_host()->SetNeedsCommit();
+
   return PP_OK_COMPLETIONPENDING;
 }