Clear the clipboard closing Incognito window

ui/base/clipboard/clipboard.h

Index: ui/base/clipboard/clipboard.h
diff --git a/ui/base/clipboard/clipboard.h b/ui/base/clipboard/clipboard.h
index 94d78712f26c6c6e629b33513e43ffd1831224d1..87cf29cef82a4d28921e7a116e84d91a723a3067 100644
--- a/ui/base/clipboard/clipboard.h
+++ b/ui/base/clipboard/clipboard.h
@@ -11,6 +11,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
+#include "base/observer_list.h"
 #include "base/process.h"
 #include "base/shared_memory.h"
 #include "base/string16.h"
@@ -132,6 +133,7 @@ class UI_EXPORT Clipboard : NON_EXPORTED_BASE(public base::ThreadChecker) {
     CBF_BITMAP,
     CBF_SMBITMAP,  // Bitmap from shared memory.
     CBF_DATA,  // Arbitrary block of bytes.
+    CBF_INCOGNITO_MARKER, // Signifies that data came from Incognito mode.
   };
 
   // ObjectMap is a map from ObjectType to associated data.
@@ -162,6 +164,8 @@ class UI_EXPORT Clipboard : NON_EXPORTED_BASE(public base::ThreadChecker) {
   //               size         gfx::Size struct
   // CBF_DATA      format       char array
   //               data         byte array
+  // CBF_INCOGNITO_MARKER
+  //               data         byte array
   typedef std::vector<char> ObjectMapParam;
   typedef std::vector<ObjectMapParam> ObjectMapParams;
   typedef std::map<int /* ObjectType */, ObjectMapParams> ObjectMap;
@@ -174,6 +178,22 @@ class UI_EXPORT Clipboard : NON_EXPORTED_BASE(public base::ThreadChecker) {
     BUFFER_SELECTION,
   };
 
+  class ClipboardObserver {
+   public:
+    // Called at the end of Clipboard::WriteObjects()
+    virtual void OnWriteObjects(Buffer buffer) = 0;

[dcheng, 2013/01/31 22:25:56]

I feel a little uncertain about having a ClipboardObserver that isn't really a
clipboard observer (it only triggers in one very specific circumstance)

Would it be better to write a UI test util that detects when the clipboard
changes? Win and Linux both have support for receiving notifications when the
clipboard changes; Mac can be implemented by polling.

[battre, 2013/02/01 09:36:39]

I think the polling on Mac would be very awkward. In particular it would make
the tests slow and potentially flaky (polling is highly discouraged in testing
by Pawel). Also we don't need to do the polling unless we are in unit tests.

Given that we need this observer only for unit testing, my proposal would be the
following:

Rename ClipboardObserver to ClipboardObserverForTesting and add a comment
// This observer notices and reports only write operations though class
Clipboard.
// Modifications from other applications in the operating system are not
reported.

WDYT?

+   protected:
+    virtual ~ClipboardObserver() {}
+  };
+
+  void AddObserver(ClipboardObserver* obs) {
+    observer_list_.AddObserver(obs);
+  }
+
+  void RemoveObserver(ClipboardObserver* obs) {
+    observer_list_.RemoveObserver(obs);
+  }
+
   static bool IsValidBuffer(int32 buffer) {
     switch (buffer) {
       case BUFFER_STANDARD:
@@ -280,6 +300,7 @@ class UI_EXPORT Clipboard : NON_EXPORTED_BASE(public base::ThreadChecker) {
   // crbug.com/158399.
   static const FormatType& GetWebCustomDataFormatType();
   static const FormatType& GetPepperCustomDataFormatType();
+  static const FormatType& GetIncognitoMarkerFormatType();
 
   // Embeds a pointer to a SharedMemory object pointed to by |bitmap_handle|
   // belonging to |process| into a shared bitmap [CBF_SMBITMAP] slot in
@@ -307,6 +328,8 @@ class UI_EXPORT Clipboard : NON_EXPORTED_BASE(public base::ThreadChecker) {
 
   void DispatchObject(ObjectType type, const ObjectMapParams& params);
 
+  void WriteObjectsImpl(Buffer buffer, const ObjectMap& objects);
+
   void WriteText(const char* text_data, size_t text_len);
 
   void WriteHTML(const char* markup_data,
@@ -382,6 +405,7 @@ class UI_EXPORT Clipboard : NON_EXPORTED_BASE(public base::ThreadChecker) {
   class AuraX11Details;
   scoped_ptr<AuraX11Details> aurax11_details_;
 #endif
+  ObserverList<ClipboardObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(Clipboard);
 };