Do not forward declare OBJC types.

We have to disable forward declaration of objective-c
types in Qt when building chromium code.
Chromium does have different, incompatible
forward declarations.

Change-Id: Ib7f7e9839e5c85d758d1e5bb921e67c57a55c4ef
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>

lib/lib.pro

@@ -10,7 +10,8 @@ TEMPLATE = lib
 TARGET = Qt5WebEngineCore
 
 # Defining keywords such as 'signal' clashes with the chromium code base.
-DEFINES += QT_NO_KEYWORDS
+DEFINES += QT_NO_KEYWORDS \
+           Q_FORWARD_DECLARE_OBJC_CLASS=QT_FORWARD_DECLARE_CLASS
 
 # We need a way to tap into gyp´s Debug vs. Release configuration
 PER_CONFIG_DEFINES = QTWEBENGINEPROCESS_PATH=\\\"$$getOutDir()/%config/$$QTWEBENGINEPROCESS_NAME\\\"

shared/shared.pro

@@ -10,7 +10,8 @@ CONFIG += static
 TARGET = qtwebengine_shared
 
 # Defining keywords such as 'signal' clashes with the chromium code base.
-DEFINES += QT_NO_KEYWORDS
+DEFINES += QT_NO_KEYWORDS \
+           Q_FORWARD_DECLARE_OBJC_CLASS=QT_FORWARD_DECLARE_CLASS
 
 # We need a way to tap into gyp´s Debug vs. Release configuration
 PER_CONFIG_DEFINES = QTWEBENGINEPROCESS_PATH=\\\"$$getOutDir()/%config/$$QTWEBENGINEPROCESS_NAME\\\"