Remove obsolete 'PlatformView::size_' member variable (#30812)

Author: ColdPaleLight

shell/common/platform_view.cc

@@ -16,7 +16,6 @@ namespace flutter {
 PlatformView::PlatformView(Delegate& delegate, TaskRunners task_runners)
     : delegate_(delegate),
       task_runners_(std::move(task_runners)),
-      size_(SkISize::Make(0, 0)),
       weak_factory_(this) {}
 
 PlatformView::~PlatformView() = default;

shell/common/platform_view.h

@@ -25,7 +25,6 @@
 #include "flutter/shell/common/platform_message_handler.h"
 #include "flutter/shell/common/pointer_data_dispatcher.h"
 #include "flutter/shell/common/vsync_waiter.h"
-#include "third_party/skia/include/core/SkSize.h"
 #include "third_party/skia/include/gpu/GrDirectContext.h"
 
 namespace flutter {
@@ -804,7 +803,6 @@ class PlatformView {
   PlatformView::Delegate& delegate_;
   const TaskRunners task_runners_;
   PointerDataPacketConverter pointer_data_packet_converter_;
-  SkISize size_;
   fml::WeakPtrFactory<PlatformView> weak_factory_;  // Must be the last member.
 
  private: