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.

libcef_dll/ctocpp/browser_ctocpp.cc

@@ -9,14 +9,13 @@
 // implementations. See the translator.README.txt file in the tools directory
 // for more information.
 //
-// $hash=3a2fc11634093382ba9354ca64a2da50bb677e9f$
+// $hash=cfc1a36565ce6b7c8db6a26532319da2fbef9f2a$
 //
 
 #include "libcef_dll/ctocpp/browser_ctocpp.h"
 #include <algorithm>
 #include "libcef_dll/ctocpp/browser_host_ctocpp.h"
 #include "libcef_dll/ctocpp/frame_ctocpp.h"
-#include "libcef_dll/ctocpp/process_message_ctocpp.h"
 #include "libcef_dll/shutdown_checker.h"
 #include "libcef_dll/transfer_util.h"
 
@@ -373,31 +372,6 @@ void CefBrowserCToCpp::GetFrameNames(std::vector<CefString>& names) {
   }
 }
 
-NO_SANITIZE("cfi-icall")
-bool CefBrowserCToCpp::SendProcessMessage(
-    CefProcessId target_process,
-    CefRefPtr<CefProcessMessage> message) {
-  shutdown_checker::AssertNotShutdown();
-
-  cef_browser_t* _struct = GetStruct();
-  if (CEF_MEMBER_MISSING(_struct, send_process_message))
-    return false;
-
-  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
-
-  // Verify param: message; type: refptr_same
-  DCHECK(message.get());
-  if (!message.get())
-    return false;
-
-  // Execute
-  int _retval = _struct->send_process_message(
-      _struct, target_process, CefProcessMessageCToCpp::Unwrap(message));
-
-  // Return type: bool
-  return _retval ? true : false;
-}
-
 // CONSTRUCTOR - Do not edit by hand.
 
 CefBrowserCToCpp::CefBrowserCToCpp() {}