Issue #80 - reinstated unified building for some large chunks of our code.

This should reduce compile complexity saving time and reducing linker stress.

dom/ipc/moz.build

@@ -43,13 +43,11 @@ EXPORTS.mozilla += [
     'ProcessPriorityManager.h',
 ]
 
-SOURCES += [
+UNIFIED_SOURCES += [
     'AppProcessChecker.cpp',
-    'Blob.cpp',
     'ColorPickerParent.cpp',
     'ContentBridgeChild.cpp',
     'ContentBridgeParent.cpp',
-    'ContentChild.cpp',
     'ContentParent.cpp',
     'ContentProcess.cpp',
     'ContentProcessManager.cpp',
@@ -58,7 +56,6 @@ SOURCES += [
     'nsIContentParent.cpp',
     'PermissionMessageUtils.cpp',
     'PreallocatedProcessManager.cpp',
-    'ProcessHangMonitor.cpp',
     'ProcessPriorityManager.cpp',
     'ScreenManagerParent.cpp',
     'StructuredCloneData.cpp',
@@ -68,6 +65,14 @@ SOURCES += [
     'TabParent.cpp',
 ]
 
+# Blob.cpp cannot be compiled in unified mode because it triggers a fatal gcc warning.
+# ContentChild.cpp cannot be compiled in unified mode on  linux due to Time conflict
+SOURCES += [
+    'Blob.cpp',
+    'ContentChild.cpp',
+    'ProcessHangMonitor.cpp',
+]
+
 IPDL_SOURCES += [
     'BlobTypes.ipdlh',
     'DOMTypes.ipdlh',