Create a minimal webkit_common static library for use in browser process

Source/core/core.gypi

Index: Source/core/core.gypi
diff --git a/Source/core/core.gypi b/Source/core/core.gypi
index 2e0a531413121089540f3072a8df361a8d8beb59..1f5072e51645a8e7eaf2dbb9f8110504262f1983 100644
--- a/Source/core/core.gypi
+++ b/Source/core/core.gypi
@@ -2516,7 +2516,6 @@
             'platform/ScrollbarThemeComposite.h',
             'platform/SecureTextInput.cpp',
             'platform/SecureTextInput.h',
-            'platform/SerializedResource.h',
             'platform/SharedBuffer.cpp',
             'platform/SharedBufferChunkReader.cpp',
             'platform/SharedTimer.h',
@@ -3006,6 +3005,7 @@
             'platform/mac/LocalCurrentGraphicsContext.mm',
             'platform/mac/NSScrollerImpDetails.h',
             'platform/mac/NSScrollerImpDetails.mm',
+            'platform/mac/PurgeableBufferMac.cpp',
             'platform/mac/ScrollAnimatorMac.h',
             'platform/mac/ScrollAnimatorMac.mm',
             'platform/mac/ScrollElasticityController.h',
@@ -3615,12 +3615,8 @@
             'platform/chromium/support/WebActiveGestureAnimation.cpp',
             'platform/chromium/support/WebActiveGestureAnimation.h',
             'platform/chromium/support/WebAudioBus.cpp',
-            'platform/chromium/support/WebCString.cpp',
             'platform/chromium/support/WebCursorInfo.cpp',
             'platform/chromium/support/WebData.cpp',
-            'platform/chromium/support/WebDeviceMotionData.cpp',
-            'platform/chromium/support/WebFilterOperation.cpp',
-            'platform/chromium/support/WebFilterOperations.cpp',
             'platform/chromium/support/WebFloatQuad.cpp',
             'platform/chromium/support/WebHTTPBody.cpp',
             'platform/chromium/support/WebHTTPLoadInfo.cpp',
@@ -3650,10 +3646,8 @@
             'platform/chromium/support/WebSpeechSynthesisVoice.cpp',
             'platform/chromium/support/WebSpeechSynthesizerClientImpl.cpp',
             'platform/chromium/support/WebSpeechSynthesizerClientImpl.h',
-            'platform/chromium/support/WebString.cpp',
             'platform/chromium/support/WebThreadSafeData.cpp',
             'platform/chromium/support/WebTransformKeyframe.cpp',
-            'platform/chromium/support/WebURL.cpp',
             'platform/chromium/support/WebURLError.cpp',
             'platform/chromium/support/WebURLRequest.cpp',
             'platform/chromium/support/WebURLRequestPrivate.h',