Implement WebThread::{add,remove}TaskObserver.

Re-landing r113010 with clang style fixes.

R=tony@chromium.org

Review URL: http://codereview.chromium.org/8805027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@113073 0039d316-1c4b-4281-b951-d872f2087c98

webkit/glue/webthread_impl.cc

@@ -10,9 +10,48 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/message_loop.h"
+#include "base/threading/platform_thread.h"
 
 namespace webkit_glue {
 
+WebThreadBase::WebThreadBase() { }
+WebThreadBase::~WebThreadBase() { }
+
+class WebThreadBase::TaskObserverAdapter : public MessageLoop::TaskObserver {
+public:
+  TaskObserverAdapter(WebThread::TaskObserver* observer)
+      : observer_(observer) { }
+
+  // WebThread::TaskObserver does not have a willProcessTask method.
+  virtual void WillProcessTask(base::TimeTicks) OVERRIDE { }
+
+  virtual void DidProcessTask(base::TimeTicks) OVERRIDE {
+    observer_->didProcessTask();
+  }
+
+private:
+  WebThread::TaskObserver* observer_;
+};
+
+void WebThreadBase::addTaskObserver(TaskObserver* observer) {
+  CHECK(IsCurrentThread());
+  std::pair<TaskObserverMap::iterator, bool> result = task_observer_map_.insert(
+      std::make_pair(observer, static_cast<TaskObserverAdapter*>(NULL)));
+  if (result.second)
+    result.first->second = new TaskObserverAdapter(observer);
+  MessageLoop::current()->AddTaskObserver(result.first->second);
+}
+
+void WebThreadBase::removeTaskObserver(TaskObserver* observer) {
+  CHECK(IsCurrentThread());
+  TaskObserverMap::iterator iter = task_observer_map_.find(observer);
+  if (iter == task_observer_map_.end())
+    return;
+  MessageLoop::current()->RemoveTaskObserver(iter->second);
+  delete iter->second;
+  task_observer_map_.erase(iter);
+}
+
 WebThreadImpl::WebThreadImpl(const char* name)
     : thread_(new base::Thread(name)) {
   thread_->Start();
@@ -22,6 +61,7 @@ void WebThreadImpl::postTask(Task* task) {
   thread_->message_loop()->PostTask(
       FROM_HERE, base::Bind(&WebKit::WebThread::Task::run, base::Owned(task)));
 }
+
 void WebThreadImpl::postDelayedTask(
     Task* task, long long delay_ms) {
   thread_->message_loop()->PostDelayedTask(
@@ -30,6 +70,10 @@ void WebThreadImpl::postDelayedTask(
       delay_ms);
 }
 
+bool WebThreadImpl::IsCurrentThread() const {
+  return thread_->thread_id() == base::PlatformThread::CurrentId();
+}
+
 WebThreadImpl::~WebThreadImpl() {
   thread_->Stop();
 }
@@ -52,6 +96,10 @@ void WebThreadImplForMessageLoop::postDelayedTask(
       delay_ms);
 }
 
+bool WebThreadImplForMessageLoop::IsCurrentThread() const {
+  return message_loop_->BelongsToCurrentThread();
+}
+
 WebThreadImplForMessageLoop::~WebThreadImplForMessageLoop() {
 }
 

webkit/glue/webthread_impl.h

@@ -4,6 +4,8 @@
 #ifndef WEBKIT_GLUE_WEBTHREAD_IMPL_H_
 #define WEBKIT_GLUE_WEBTHREAD_IMPL_H_
 
+#include <map>
+
 #include "base/threading/thread.h"
 #include "base/memory/scoped_ptr.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebThread.h"
@@ -11,9 +13,28 @@
 
 namespace webkit_glue {
 
-class WebThreadImpl : public WebKit::WebThread {
+class WebThreadBase : public WebKit::WebThread {
+ public:
+  virtual ~WebThreadBase();
+
+  virtual void addTaskObserver(TaskObserver* observer);
+  virtual void removeTaskObserver(TaskObserver* observer);
+
+ protected:
+  WebThreadBase();
+
+ private:
+  class TaskObserverAdapter;
+
+  virtual bool IsCurrentThread() const = 0;
+
+  typedef std::map<TaskObserver*, TaskObserverAdapter*> TaskObserverMap;
+  TaskObserverMap task_observer_map_;
+};
+
+class WebThreadImpl : public WebThreadBase {
  public:
-  WEBKIT_GLUE_EXPORT WebThreadImpl(const char* name);
+  WEBKIT_GLUE_EXPORT explicit WebThreadImpl(const char* name);
   WEBKIT_GLUE_EXPORT virtual ~WebThreadImpl();
 
   virtual void postTask(Task* task) OVERRIDE;
@@ -21,19 +42,21 @@ class WebThreadImpl : public WebKit::WebThread {
 
   MessageLoop* message_loop() const { return thread_->message_loop(); }
 
- protected:
+ private:
+  virtual bool IsCurrentThread() const OVERRIDE;
   scoped_ptr<base::Thread> thread_;
 };
 
-class WebThreadImplForMessageLoop : public WebKit::WebThread {
+class WebThreadImplForMessageLoop : public WebThreadBase {
  public:
-  WebThreadImplForMessageLoop(base::MessageLoopProxy* message_loop);
+  explicit WebThreadImplForMessageLoop(base::MessageLoopProxy* message_loop);
   virtual ~WebThreadImplForMessageLoop();
 
   virtual void postTask(Task* task) OVERRIDE;
   virtual void postDelayedTask(Task* task, long long delay_ms) OVERRIDE;
 
- protected:
+ private:
+  virtual bool IsCurrentThread() const OVERRIDE;
   scoped_refptr<base::MessageLoopProxy> message_loop_;
 };