[DevTools] Implement DevToolsManager::Observer which notifies about target updates.

content/browser/devtools/devtools_manager.cc

Index: content/browser/devtools/devtools_manager.cc
diff --git a/content/browser/devtools/devtools_manager.cc b/content/browser/devtools/devtools_manager.cc
index 6d8da5399e650920f57b84b69e2f36ba01b09f7c..bdef4afb819bbae40afffaf0917c3d74b1508cc7 100644
--- a/content/browser/devtools/devtools_manager.cc
+++ b/content/browser/devtools/devtools_manager.cc
@@ -6,10 +6,10 @@
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
+#include "content/browser/devtools/devtools_agent_host_impl.h"
 #include "content/browser/devtools/devtools_netlog_observer.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
-#include "content/public/browser/devtools_manager_delegate.h"
 
 namespace content {
 
@@ -20,31 +20,105 @@ DevToolsManager* DevToolsManager::GetInstance() {
 
 DevToolsManager::DevToolsManager()
     : delegate_(GetContentClient()->browser()->GetDevToolsManagerDelegate()),
-      client_count_(0) {
+      update_target_list_required_(false),
+      update_target_list_scheduled_(false),
+      update_target_list_callback_(base::Bind(
+          &DevToolsManager::UpdateTargetListThrottled,
+          base::Unretained(this))) {
 }
 
 DevToolsManager::~DevToolsManager() {
-  DCHECK(!client_count_);
+  DCHECK(!attached_hosts_.size());
+  update_target_list_callback_.Cancel();
 }
 
-void DevToolsManager::OnClientAttached() {
-  if (!client_count_) {
-    BrowserThread::PostTask(
-        BrowserThread::IO,
-        FROM_HERE,
-        base::Bind(&DevToolsNetLogObserver::Attach));
+void DevToolsManager::RenderViewCreated(
+    WebContents* web_contents, RenderViewHost* rvh) {
+  if (observer_list_.might_have_observers()) {
+    // Force agent host creation.
+    DevToolsAgentHost::GetOrCreateFor(web_contents);
   }
-  client_count_++;
 }
 
-void DevToolsManager::OnClientDetached() {
-  client_count_--;
-  if (!client_count_) {
-    BrowserThread::PostTask(
-        BrowserThread::IO,
-        FROM_HERE,
-        base::Bind(&DevToolsNetLogObserver::Detach));
+void DevToolsManager::AgentHostChanged(
+    scoped_refptr<DevToolsAgentHost> agent_host) {
+  bool was_attached =
+      attached_hosts_.find(agent_host.get()) != attached_hosts_.end();
+  if (agent_host->IsAttached() && !was_attached) {
+    if (!attached_hosts_.size()) {
+      BrowserThread::PostTask(
+          BrowserThread::IO,
+          FROM_HERE,
+          base::Bind(&DevToolsNetLogObserver::Attach));
+    }
+    attached_hosts_.insert(agent_host.get());
+  } else if (!agent_host->IsAttached() && was_attached) {
+    attached_hosts_.erase(agent_host.get());
+    if (!attached_hosts_.size()) {
+      BrowserThread::PostTask(
+          BrowserThread::IO,
+          FROM_HERE,
+          base::Bind(&DevToolsNetLogObserver::Detach));
+    }
   }
+
+  UpdateTargetList();
+}
+
+void DevToolsManager::AddObserver(Observer* observer) {
+  observer_list_.AddObserver(observer);
+  UpdateTargetList();
+}
+
+void DevToolsManager::RemoveObserver(Observer* observer) {
+  observer_list_.RemoveObserver(observer);
+}
+
+void DevToolsManager::UpdateTargetList() {
+  if (!observer_list_.might_have_observers())
+    return;
+
+  update_target_list_required_ = true;
+  if (!update_target_list_scheduled_)
+    UpdateTargetListThrottled();
+}
+
+void DevToolsManager::UpdateTargetListThrottled() {
+  if (!update_target_list_required_) {
+    update_target_list_scheduled_ = false;
+    return;
+  }
+
+  update_target_list_scheduled_ = true;
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      update_target_list_callback_.callback(),
+      observer_throttle_interval_);
+
+  update_target_list_required_ = false;
+  if (!delegate_) {
+    Observer::TargetList empty_list;
+    NotifyTargetListChanged(empty_list);
+    return;
+  }
+  delegate_->EnumerateTargets(base::Bind(
+      &DevToolsManager::NotifyTargetListChanged,
+      base::Unretained(this)));
+}
+
+void DevToolsManager::NotifyTargetListChanged(
+    const Observer::TargetList& targets) {
+  FOR_EACH_OBSERVER(Observer, observer_list_, TargetListChanged(targets));
+}
+
+// static
+base::TimeDelta DevToolsManager::observer_throttle_interval_ =
+    base::TimeDelta::FromMilliseconds(500);
+
+// static
+void DevToolsManager::SetObserverThrottleIntervalForTest(
+    base::TimeDelta interval) {
+  observer_throttle_interval_ = interval;
 }
 
 }  // namespace content