New implementation of font precache on Windows.

content/common/child_process_host.h

Index: content/common/child_process_host.h
diff --git a/content/common/child_process_host.h b/content/common/child_process_host.h
index 8637c184c9cf9cc3fce8128d51cc1d53f7ba7504..da9edfb5d71463590ae4ace4e66685a586efd6f7 100644
--- a/content/common/child_process_host.h
+++ b/content/common/child_process_host.h
@@ -8,6 +8,7 @@
 
 #include <string>
 #include <vector>
+#include <map>
 
 #include "build/build_config.h"
 
@@ -27,6 +28,12 @@ namespace IPC {
 class Message;
 }
 
+#if defined(OS_WIN)
+// Types used in PreCacheFont
+typedef std::vector<std::wstring> FontNameVector;
+typedef std::map<int, FontNameVector> PidToFontNames;
+#endif  // defined(OS_WIN)
+
 // Provides common functionality for hosting a child process and processing IPC
 // messages between the host and the child process. Subclasses are responsible
 // for the actual launching and terminating of the child processes.
@@ -86,7 +93,8 @@ class ChildProcessHost : public IPC::Channel::Listener,
 #if defined(OS_WIN)
   // See comments in the cc file. This is a common hack needed for a process
   // hosting a sandboxed child process. Hence it lives in this file.
-  static void PreCacheFont(LOGFONT font);
+  static void PreCacheFont(LOGFONT font, int pid);
+  static void ReleaseCachedFont(int pid);
 #endif  // defined(OS_WIN)
 
   // IPC::Message::Sender implementation.
@@ -143,6 +151,33 @@ class ChildProcessHost : public IPC::Channel::Listener,
 
   ListenerHook listener_;
 
+#if defined (OS_WIN)
+  class FontCache {
+   public:
+    FontCache() {}  // Make Singleton<> happy.
+    ~FontCache() {}
+
+    static FontCache* GetInstance();
+    void PreCacheFont(LOGFONT font, int pid);
+    void ReleaseCachedFont(int pid);
+
+   private:
+    struct CacheElement {
+      CacheElement();
+      ~CacheElement();
+
+      HFONT font_;
+      HDC dc_;
+      int ref_count_;
+    };
+    std::map<std::wstring, CacheElement> cache_;
+    PidToFontNames pid_font_map_;
+    base::Lock mutex_;
+
+    DISALLOW_COPY_AND_ASSIGN(FontCache);
+  };
+#endif
+
   bool opening_channel_;  // True while we're waiting the channel to be opened.
   scoped_ptr<IPC::Channel> channel_;
   std::string channel_id_;