Replace RenderArena with PartitionAlloc.

Source/core/core.gypi

 {
     'variables': {
         'core_idl_files': [
             'css/CSS.idl',
             'css/CSSCharsetRule.idl',
             'css/CSSFontFaceLoadEvent.idl',
             'css/CSSFontFaceRule.idl',
             'css/CSSHostRule.idl',
             'css/CSSImportRule.idl',
             'css/CSSMediaRule.idl',
@@ skipping 1284 matching lines @@
             'rendering/InlineIterator.h',
             'rendering/InlineTextBox.cpp',
             'rendering/ImageQualityController.h',
             'rendering/ImageQualityController.cpp',
             'rendering/LayoutState.cpp',
             'rendering/LayoutRepainter.cpp',
             'rendering/PointerEventsHitRules.cpp',
             'rendering/PointerEventsHitRules.h',
             'rendering/RenderApplet.cpp',
             'rendering/RenderApplet.h',
-            'rendering/RenderArena.cpp',
-            'rendering/RenderArena.h',
             'rendering/RenderBR.cpp',
             'rendering/RenderBlock.cpp',
             'rendering/RenderBlockLineLayout.cpp',
             'rendering/RenderBox.cpp',
             'rendering/RenderBoxModelObject.cpp',
             'rendering/RenderButton.cpp',
             'rendering/RenderButton.h',
             'rendering/RenderCombineText.cpp',
             'rendering/RenderCombineText.h',
             'rendering/RenderCounter.cpp',
@@ skipping 1122 matching lines @@
             'html/track/TrackEvent.cpp',
             'html/track/WebVTTElement.cpp',
             'html/track/WebVTTElement.h',
             'html/track/WebVTTParser.cpp',
             'html/track/WebVTTParser.h',
             'html/track/WebVTTToken.h',
             'html/track/WebVTTTokenizer.cpp',
             'html/track/WebVTTTokenizer.h',
         ],
         'webcore_platform_files': [
-            'platform/Arena.cpp',
-            'platform/Arena.h',
             'platform/AsyncFileSystem.h',
             'platform/AsyncFileSystemCallbacks.h',
             'platform/CalculationValue.cpp',
             'platform/CalculationValue.h',
             'platform/Clock.cpp',
             'platform/Clock.h',
             'platform/ContentType.cpp',
             'platform/ContentType.h',
             'platform/ContextMenu.cpp',
             'platform/ContextMenuItem.cpp',
@@ skipping 16 matching lines @@
             'platform/Language.cpp',
             'platform/LayoutTestSupport.cpp',
             'platform/LayoutTestSupport.h',
             'platform/Length.cpp',
             'platform/LengthBox.cpp',
             'platform/LinkHash.cpp',
             'platform/Logging.cpp',
             'platform/MIMETypeFromURL.cpp',
             'platform/MIMETypeFromURL.h',
             'platform/NotImplemented.cpp',
+            'platform/Partitions.cpp',
+            'platform/Partitions.h',
             'platform/Pasteboard.h',
             'platform/PlatformEvent.cpp',
             'platform/PlatformEvent.h',
             'platform/PlatformInstrumentation.cpp',
             'platform/PlatformInstrumentation.h',
             'platform/PlatformMemoryInstrumentation.cpp',
             'platform/PlatformMemoryInstrumentation.h',
             'platform/PlatformSpeechSynthesisUtterance.cpp',
             'platform/PlatformSpeechSynthesisUtterance.h',
             'platform/PlatformSpeechSynthesisVoice.cpp',
@@ skipping 1194 matching lines @@
                 'bison_exe': 'bison',
                 # We specify a preprocess so it happens locally and won't get
                 # distributed to goma.
                 # FIXME: /usr/bin/gcc won't exist on OSX forever. We want to
                 # use /usr/bin/clang once we require Xcode 4.x.
                 'preprocessor': '--preprocessor "/usr/bin/gcc -E -P -x c++"'
               }],
          ],
     }
 }