Reduce the frequency of connection-related renderer crashes (see #3664)

- Use ResetWithReason to report intentional browser side disconnects of
  existing Mojo connections. Don't retry for those disconnects.
- Add set_disconnect_with_reason_and_result_handler in Chromium/Mojo to
  expose the MojoResult code for failed connections, allowing
  identification of connections that are intentionally unbound on the
  browser side.
- Optimize initial reconnect delay for known disconnect cases such as
  navigation-related and bfcache changes.
- Remove connection timeout and increase total connection deadline by
  100% to further reduce crash rates on slower machines.
- Only fail fatally for main frames (not sub-frames) in cases where the
  connection fails or disconnects for unknown reasons.
- Improve connection debug logging when running with
  `--enable-logging --vmodule=*frame*=1 --log-file=C:\temp\log.txt`

libcef/common/frame_util.h

@@ -86,6 +86,16 @@ std::string GetFrameDebugString(
 std::string GetFrameDebugString(
     const content::GlobalRenderFrameHostToken& global_token);
 
+// Used in combination with ResetWithReason() to report mojo connection
+// disconnect reasons. |kNoReason| (0) is the default when a mojo connection
+// disconnects without a specified reason.
+enum class ResetReason : uint32_t {
+  kNoReason,
+  kDeleted,
+  kDetached,
+  kExcluded,
+};
+
 }  // namespace frame_util
 
 #endif  // CEF_LIBCEF_COMMON_FRAME_UTIL_H_