Fix bug causing blank pages on resume of Chrome for Android.

content/browser/android/content_view_statics.cc

Index: content/browser/android/content_view_statics.cc
diff --git a/content/browser/android/content_view_statics.cc b/content/browser/android/content_view_statics.cc
index e176564c4a0f5a430aad40adaddc2d7aef806c05..979ae3b5ec4871f1f70363292f569a7edeab429c 100644
--- a/content/browser/android/content_view_statics.cc
+++ b/content/browser/android/content_view_statics.cc
@@ -15,6 +15,7 @@
 #include "content/common/android/address_parser.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_process_host_observer.h"
 #include "jni/ContentViewStatics_jni.h"
 
 using base::android::ConvertJavaStringToUTF16;
@@ -34,7 +35,29 @@ namespace {
 // suspend calls are refcounted within WebKitPlatformSupport and it expects a
 // perfectly matched number of resume calls.
 // Note that this vector is only accessed from the UI thread.
-base::LazyInstance<std::vector<int /* process id */> > g_suspended_processes =
+base::LazyInstance<std::vector<int /* RenderProcessHost id */> >
+    g_suspended_processes = LAZY_INSTANCE_INITIALIZER;
+
+// Listens for RenderProcessHosts whose renderers have crashed. This is
+// necessary to ensure that we don't over-resume a RenderProcess as described
+// above.
+class SuspendedProcessWatcher : public content::RenderProcessHostObserver {
+  virtual void RenderProcessExited(content::RenderProcessHost* host,
+                                   base::ProcessHandle handle,
+                                   base::TerminationStatus status,
+                                   int exit_code) OVERRIDE {
+    std::vector<int>* suspended_processes = g_suspended_processes.Pointer();
+    std::vector<int>::iterator pos = std::find(suspended_processes->begin(),
+                                               suspended_processes->end(),
+                                               host->GetID());
+    if (pos != suspended_processes->end()) {
+      host->RemoveObserver(this);
+      suspended_processes->erase(pos);
+    }
+  }
+};
+
+base::LazyInstance<SuspendedProcessWatcher> g_suspended_processes_watcher =
     LAZY_INSTANCE_INITIALIZER;
 
 // Suspends timers in all current render processes.
@@ -45,6 +68,7 @@ void SuspendWebKitSharedTimers(std::vector<int>* suspended_processes) {
     content::RenderProcessHost* host = i.GetCurrentValue();
     suspended_processes->push_back(host->GetID());
     host->Send(new ViewMsg_SetWebKitSharedTimersSuspended(true));
+    host->AddObserver(g_suspended_processes_watcher.Pointer());

[klobag.chromium, 2014/02/25 22:19:27]

Hmm, are we calling this every time in suspend? Are we hitting the following
NOTREACHED() if you hit HOME/Chrome/HOME?

  // Add an observer to the list.  An observer should not be added to
  // the same list more than once.
  void AddObserver(ObserverType* obs) {
    if (std::find(observers_.begin(), observers_.end(), obs)
        != observers_.end()) {
      NOTREACHED() << "Observers can only be added once!";
      return;
    }
    observers_.push_back(obs);
  }

[Yaron, 2014/03/08 00:56:02]

Done.

   }
 }