Show device attach web intent picker dialog only if we have registered services.

chrome/browser/intents/device_attached_intent_source.h

Index: chrome/browser/intents/device_attached_intent_source.h
diff --git a/chrome/browser/intents/device_attached_intent_source.h b/chrome/browser/intents/device_attached_intent_source.h
index f8c914c0b4988e5ae7f8541ec5b9e35e3cf5e05e..99fb7b97d5694a16f8955c4bd26887398710ac37 100644
--- a/chrome/browser/intents/device_attached_intent_source.h
+++ b/chrome/browser/intents/device_attached_intent_source.h
@@ -5,6 +5,7 @@
 #ifndef CHROME_BROWSER_INTENTS_DEVICE_ATTACHED_INTENT_SOURCE_H_
 #define CHROME_BROWSER_INTENTS_DEVICE_ATTACHED_INTENT_SOURCE_H_
 
+#include "base/memory/weak_ptr.h"
 #include "base/system_monitor/system_monitor.h"
 
 class Browser;
@@ -21,7 +22,8 @@ class WebContentsDelegate;
 //   root_path = the File Path at which the device is accessible
 //   filesystem_id = registered isolated file system identifier
 class DeviceAttachedIntentSource
-    : public base::SystemMonitor::DevicesChangedObserver {
+    : public base::SystemMonitor::DevicesChangedObserver,
+      public base::SupportsWeakPtr<DeviceAttachedIntentSource> {

[James Hawkins, 2012/08/06 16:36:36]

Use WeakPtrFactory instead.

[kmadhusu, 2012/08/06 18:11:52]

As per the comments in base/memory/weak_ptr.h,

WeakPtrFactory is helpful only if you need weak pointers within the
implementation of a class.

SupportWeakPtr is useful in cases where you want others to be able to get a weak
pointer to your class.

In my case, I just want DispatchIntentTaskHelper class to have a weak pointer of
DeviceAttachedIntentSource class. That is the reason I used SupportsWeakPtr. Can
you explain why I need to use WeakPtrFactory?

  public:
   DeviceAttachedIntentSource(Browser* browser,
                              content::WebContentsDelegate* delegate);
@@ -35,6 +37,11 @@ class DeviceAttachedIntentSource
       const FilePath::StringType& location) OVERRIDE;
   virtual void OnMediaDeviceDetached(const std::string& id) OVERRIDE;
 
+  // Dispatches web intents for the attached media device specified by
+  // |device_info|.
+  void DispatchIntentsForService(
+      const base::SystemMonitor::MediaDeviceInfo& device_info);
+
  private:
   typedef std::map<std::string, base::SystemMonitor::MediaDeviceInfo>
       DeviceIdToInfoMap;