[Reland] Refactor the selection code in EventHandler

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 1359 matching lines @@
             'editing/RemoveFormatCommand.h',
             'editing/RemoveNodeCommand.cpp',
             'editing/RemoveNodeCommand.h',
             'editing/RemoveNodePreservingChildrenCommand.cpp',
             'editing/RemoveNodePreservingChildrenCommand.h',
             'editing/RenderedPosition.cpp',
             'editing/RenderedPosition.h',
             'editing/ReplaceNodeWithSpanCommand.cpp',
             'editing/ReplaceNodeWithSpanCommand.h',
             'editing/ReplaceSelectionCommand.cpp',
+            'editing/SelectionController.cpp',
             'editing/SelectionType.h',

[tkent, 2015/05/20 03:31:01]

Add SelectionController.h too.

[Miyoung Shin(g), 2015/05/20 15:53:40]

Done.

             'editing/SetNodeAttributeCommand.cpp',
             'editing/SetNodeAttributeCommand.h',
             'editing/SimplifyMarkupCommand.cpp',
             'editing/SmartReplaceCF.cpp',
             'editing/SmartReplaceICU.cpp',
             'editing/SpellCheckRequester.cpp',
             'editing/SpellCheckRequester.h',
             'editing/SpellChecker.cpp',
             'editing/SpellChecker.h',
             'editing/SplitElementCommand.cpp',
@@ skipping 2508 matching lines @@
             'style/ComputedStyleTest.cpp',
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }