Don't save last used locations in open and save dialogs when in incognito mode.

chrome/browser/profile.h

Index: chrome/browser/profile.h
diff --git a/chrome/browser/profile.h b/chrome/browser/profile.h
index 118608c4684b6a462a8be1f382585abd77252ced..cd87ca2b7a8ba06985169770901df81bc1bcbe55 100644
--- a/chrome/browser/profile.h
+++ b/chrome/browser/profile.h
@@ -416,6 +416,10 @@ class Profile {
   // Returns the new tab page resource cache.
   virtual NTPResourceCache* GetNTPResourceCache() = 0;
 
+  // Returns the last directory that was chosen for uploading or opening a file.
+  virtual FilePath last_selected_directory() = 0;
+  virtual void set_last_selected_directory(const FilePath& path) = 0;
+
 #ifdef UNIT_TEST
   // Use with caution.  GetDefaultRequestContext may be called on any thread!
   static void set_default_request_context(URLRequestContextGetter* c) {
@@ -536,6 +540,8 @@ class ProfileImpl : public Profile,
   virtual void InitExtensions();
   virtual void InitWebResources();
   virtual NTPResourceCache* GetNTPResourceCache();
+  virtual FilePath last_selected_directory();
+  virtual void set_last_selected_directory(const FilePath& path);
   virtual ProfileSyncService* GetProfileSyncService();
   void InitSyncService();
   virtual CloudPrintProxyService* GetCloudPrintProxyService();