Add debugging info for software compositor swap.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index f52e90f609c6e3437d88536214b4c669dc10e4ce..46195d145f540965764e6002ee206c8d1d8f31f7 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -1585,7 +1585,16 @@ void RenderWidgetHostViewAura::SwapSoftwareFrame(
       new base::SharedMemory(frame_data->handle, true));
 #endif
 
-  if (!shared_memory->Map(size_in_bytes)) {
+  if (!shared_memory->Map(0)) {
+    DLOG(ERROR) << "Unable to map renderer memory.";
+    RecordAction(UserMetricsAction("BadMessageTerminate_RWHVA1"));
+    host_->GetProcess()->ReceivedBadMessage();

[piman, 2013/10/23 00:10:15]

TBH this could fail if we're out of address space (or file descriptors - you may
want to add one more check, before this, on the handle) in the browser. I'm not
sure killing the renderer is the right thing to do in this case, but again, we
can't really do anything good either way :(

+    return;
+  }
+
+  if (shared_memory->mapped_size() < size_in_bytes) {
+    DLOG(ERROR) << "Shared memory too small for given rectangle";
+    RecordAction(UserMetricsAction("BadMessageTerminate_RWHVA2"));
     host_->GetProcess()->ReceivedBadMessage();
     return;
   }