Navigation transitions: Place transition page in same process as destination page.

content/browser/transition_request_manager.h

Index: content/browser/transition_request_manager.h
diff --git a/content/browser/transition_request_manager.h b/content/browser/transition_request_manager.h
index 9ef969b49dba26cbdaad5a97f9df2c9161a3133a..6fdf10f3db3219dcf80100d45e448af6e4eb94ae 100644
--- a/content/browser/transition_request_manager.h
+++ b/content/browser/transition_request_manager.h
@@ -5,7 +5,9 @@
 #ifndef CONTENT_BROWSER_TRANSITION_REQUEST_MANAGER_H_
 #define CONTENT_BROWSER_TRANSITION_REQUEST_MANAGER_H_
 
+#include <map>
 #include <set>
+#include <string>
 #include <utility>
 
 #include "base/basictypes.h"
@@ -14,6 +16,8 @@
 template <typename T>
 struct DefaultSingletonTraits;
 
+class GURL;
+
 namespace content {
 
 // TransitionRequestManager is used to handle bookkeeping for transition
@@ -27,6 +31,8 @@ class TransitionRequestManager {
   // Returns the singleton instance.
   CONTENT_EXPORT static TransitionRequestManager* GetInstance();
 
+  // Accessed from IO thread only ----------------------------------------------
+
   // Returns whether the RenderFrameHost specified by the given IDs currently
   // has a pending transition request. If so, we will have to delay the
   // response until the embedder resumes the request.
@@ -38,9 +44,22 @@ class TransitionRequestManager {
                                                      int render_frame_id,
                                                      bool has_pending);
 
+  // Accessed from UI thread only ----------------------------------------------
+
+  // These functions are used to store the process ID for an outgoing
+  // navigation, so that the same renderer can be reused by the transition.
+  void AddPendingTransitionProcessID(const GURL& token, int process_id);
+  void ClearPendingTransitionProcessID(const GURL& token);
+  int GetPendingTransitionProcessIDByToken(const GURL& token);
+
+  // Creates a unique transition url that is used to identify which process
+  // to use during a transition.
+  GURL CreateTransitionURL();
+
  private:
   friend struct DefaultSingletonTraits<TransitionRequestManager>;
   typedef std::set<std::pair<int, int> > RenderFrameSet;
+  typedef std::map<std::string, int> ProcessIDMap;
 
   TransitionRequestManager();
   ~TransitionRequestManager();
@@ -51,6 +70,11 @@ class TransitionRequestManager {
   // between IO->UI->IO threads.
   RenderFrameSet pending_transition_frames_;
 
+  // Map of transition urls to process ids for process sharing.
+  ProcessIDMap transition_process_ids_;
+
+  int transition_unique_ids_;
+
   DISALLOW_COPY_AND_ASSIGN(TransitionRequestManager);
 };