Fix PluginMessageLoopProxy::BelingsToCurrentThread() to always return correct result.

BUG=
TEST=Host plugin doesn't DCHECK when shutting down.


Review URL: http://codereview.chromium.org/8086015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@103412 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 11 insertions, 8 deletions

diff --git a/remoting/base/plugin_message_loop_proxy.cc b/remoting/base/plugin_message_loop_proxy.cc
index 9022a78..3a8b48e 100644
--- a/remoting/base/plugin_message_loop_proxy.cc
+++ b/remoting/base/plugin_message_loop_proxy.cc
@@ -9,7 +9,8 @@
 namespace remoting {
 
 PluginMessageLoopProxy::PluginMessageLoopProxy(Delegate* delegate)
-    : delegate_(delegate) {
+    : plugin_thread_id_(base::PlatformThread::CurrentId()),
+      delegate_(delegate) {
 }
 
 PluginMessageLoopProxy::~PluginMessageLoopProxy() {
@@ -18,7 +19,7 @@ PluginMessageLoopProxy::~PluginMessageLoopProxy() {
 void PluginMessageLoopProxy::Detach() {
   base::AutoLock auto_lock(lock_);
   if (delegate_) {
-    DCHECK(delegate_->IsPluginThread());
+    DCHECK(BelongsToCurrentThread());
     delegate_ = NULL;
   }
 }
@@ -95,11 +96,10 @@ bool PluginMessageLoopProxy::PostNonNestableDelayedTask(
 }
 
 bool PluginMessageLoopProxy::BelongsToCurrentThread() {
-  base::AutoLock auto_lock(lock_);
-  if (!delegate_)
-    return false;
-
-  return delegate_->IsPluginThread();
+  // In pepper plugins ideally we should use pp::Core::IsMainThread,
+  // but it is problematic becase we would need to keep reference to
+  // Core somewhere, e.g. make the delegate ref-counted.
+  return base::PlatformThread::CurrentId() == plugin_thread_id_;
 }
 
 // static
@@ -110,6 +110,7 @@ void PluginMessageLoopProxy::TaskSpringboard(void* data) {
 }
 
 void PluginMessageLoopProxy::RunTaskIf(Task* task) {
+  DCHECK(BelongsToCurrentThread());
   // |delegate_| can be changed only from our thread, so it's safe to
   // access it without acquiring |lock_|.
   if (delegate_)
diff --git a/remoting/base/plugin_message_loop_proxy.h b/remoting/base/plugin_message_loop_proxy.h
index 04a77b5..0f53498 100644
--- a/remoting/base/plugin_message_loop_proxy.h
+++ b/remoting/base/plugin_message_loop_proxy.h
@@ -9,6 +9,7 @@
 #include "base/compiler_specific.h"
 #include "base/message_loop_proxy.h"
 #include "base/synchronization/lock.h"
+#include "base/threading/platform_thread.h"
 
 namespace remoting {
 
@@ -22,7 +23,6 @@ class PluginMessageLoopProxy : public base::MessageLoopProxy {
 
     virtual bool RunOnPluginThread(
         int delay_ms, void(function)(void*), void* data) = 0;
-    virtual bool IsPluginThread() = 0;
   };
 
   // Caller keeps ownership of delegate.
@@ -70,6 +70,8 @@ class PluginMessageLoopProxy : public base::MessageLoopProxy {
   void RunTaskIf(Task* task);
   void RunClosureIf(const base::Closure& task);
 
+  base::PlatformThreadId plugin_thread_id_;
+
   // |lock_| must be acquired when accessing |delegate_|.
   base::Lock lock_;
   Delegate* delegate_;