Move message routing from CefBrowser to CefFrame (see issue #2498).

This change moves the SendProcessMessage method from CefBrowser to CefFrame and
adds CefBrowser parameters to OnProcessMessageReceived and
OnDraggableRegionsChanged.

The internal implementation has changed as follows:
- Frame IDs are now a 64-bit combination of the 32-bit render_process_id and
  render_routing_id values that uniquely identify a RenderFrameHost (RFH).
- CefFrameHostImpl objects are now managed by CefBrowserInfo with life span tied
  to RFH expectations. Specifically, a CefFrameHostImpl object representing a
  sub-frame will be created when a RenderFrame is created in the renderer
  process and detached when the associated RenderFrame is deleted or the
  renderer process in which it runs has died.
- The CefFrameHostImpl object representing the main frame will always be valid
  but the underlying RFH (and associated frame ID) may change over time as a
  result of cross-origin navigations. Despite these changes calling LoadURL on
  the main frame object in the browser process will always navigate as expected.
- Speculative RFHs, which may be created as a result of a cross-origin
  navigation and discarded if that navigation is not committed, are now handled
  correctly (e.g. ignored in most cases until they're committed).
- It is less likely, but still possible, to receive a CefFrame object with an
  invalid frame ID (ID < 0). This can happen in cases where a RFH has not yet
  been created for a sub-frame. For example, when OnBeforeBrowse is called
  before initiating navigation in a previously nonexisting sub-frame.

To test: All tests pass with NetworkService enabled and disabled.

include/cef_api_hash.h

@@ -34,7 +34,7 @@
 // implementations. See the translator.README.txt file in the tools directory
 // for more information.
 //
-// $hash=2fc75812c34a605fb4e67a5942f6597c6dd3be78$
+// $hash=0bc0d1faa22392b4245dc6eaf56337e7847a1900$
 //
 
 #ifndef CEF_INCLUDE_API_HASH_H_
@@ -47,13 +47,13 @@
 // way that may cause binary incompatibility with other builds. The universal
 // hash value will change if any platform is affected whereas the platform hash
 // values will change only if that particular platform is affected.
-#define CEF_API_HASH_UNIVERSAL "f9715e9bc13434498505eecee052706483eb7892"
+#define CEF_API_HASH_UNIVERSAL "31b55dcbcf52e9f51fe423741f64e5c77e71c65a"
 #if defined(OS_WIN)
-#define CEF_API_HASH_PLATFORM "7bd952f75673366dc4834de5e5995798d3db91f0"
+#define CEF_API_HASH_PLATFORM "afb8ea794d1bb0f56ba5ce1718a16e5dfd64229e"
 #elif defined(OS_MACOSX)
-#define CEF_API_HASH_PLATFORM "daa91396f67341e7bde65747f69487ecde4e3cf5"
+#define CEF_API_HASH_PLATFORM "e3a279cf087095495c08fd9fa88daef5dbafff3a"
 #elif defined(OS_LINUX)
-#define CEF_API_HASH_PLATFORM "be8ed9d9ba0b53e18c5c0adae09ff841b1fa7063"
+#define CEF_API_HASH_PLATFORM "d25833941c670d82cff0aa0ccf47b557d6813634"
 #endif
 
 #ifdef __cplusplus