clean c++ code

Samples/UIWidgetsSamples_2019_4/Assets/CountDemo.cs

 using System.Collections.Generic;
-using System.Runtime.InteropServices;
+using Unity.UIWidgets.ui;
-using UnityEngine;
-using UnityEngine.UI;
-using Color = Unity.UIWidgets.ui.Color;
 using Text = Unity.UIWidgets.widgets.Text;
 using ui_ = Unity.UIWidgets.widgets.ui_;
 using TextStyle = Unity.UIWidgets.painting.TextStyle;
         {
             base.OnEnable();
         }
-        
-        #if !UNITY_EDITOR
-        internal const string dllName = "libUIWidgets_d";
-        [DllImport(dllName)]
-        static extern float TestFloat();
-        #endif
-
-            Debug.Log("???? main");
             ui_.runApp(new MyApp());
         }
 

engine/README.md

 
 Follow https://github.com/flutter/flutter/wiki/Setting-up-the-Engine-development-environment
 
-2. Compiling for Windows
-
-Follow https://github.com/flutter/flutter/wiki/Compiling-the-engine#compiling-for-windows
-
-3. Checkout flutter-1.18-candidate.5
+2. Checkout flutter-1.18-candidate.5
 
 ```
 cd engine/src/flutter
 If the compilation fails because "no available Mac SDK is found" (in flutter-1.17 the build tool will only try to find Mac 10.XX SDKs), please modify the file "/src/build/Mac/find_sdk.py" under flutter root by setting "sdks" as your current sdk, e.g., ['11.0']. 
 ### build icu
 ```
+cd <uiwidigets_dir>\engine
+```
+
+### build uiwidgets
+```
+cd <uiwidigets_dir>\engine
+mono bee.exe
 ```

engine/src/flow/raster_cache.cc

 RasterCacheResult::RasterCacheResult(sk_sp<SkImage> image,
                                      const SkRect& logical_rect)
     : image_(std::move(image)), logical_rect_(logical_rect) {}
+#if __ANDROID__
+#define ABS(x) abs(x)
+template<typename T>
+T abs(T x) {
+  if (x < 0) {
+    return -x;
+  }
+  return x;
+}
+#else 
+#define ABS(x) std::abs(x)
+#endif
 
 void RasterCacheResult::draw(SkCanvas& canvas, const SkPaint* paint) const {
   TRACE_EVENT0("uiwidgets", "RasterCacheResult::draw");
       auto a = bounds.size().width() - image_->dimensions().width();
-      if(a < 0){
-        a = -a;
-      }
-      auto b = bounds.size().height() - image_->dimensions().height();
-      if(b < 0){
-        b = -b;
-      }
-      a <= 1 &&
-      b <= 1);
+        ABS(bounds.size().width() - image_->dimensions().width()) <= 1 &&
+        ABS(bounds.size().height() - image_->dimensions().height()) <= 1);
   canvas.resetMatrix();
   canvas.drawImage(image_, bounds.fLeft, bounds.fTop, paint);
 }

engine/src/lib/ui/text/paragraph.cc

   return result;
 }
 
-// static void EncodeTextBoxes(const std::vector<txt::Paragraph::TextBox>& boxes,
-//                             float* result) {
-//   // Layout:
-//   // First value is the number of values.
-//   // Then there are boxes.size() groups of 5 which are LTRBD, where D is the
-//   // text direction index.
+static void EncodeTextBoxes(const std::vector<txt::Paragraph::TextBox>& boxes,
+                            float* result) {
+  // Layout:
+  // First value is the number of values.
+  // Then there are boxes.size() groups of 5 which are LTRBD, where D is the
+  // text direction index.
-//   unsigned long position = 0;
-//   for (unsigned long i = 0; i < boxes.size(); i++) {
-//     const txt::Paragraph::TextBox& box = boxes[i];
-//     result[position++] = box.rect.fLeft;
-//     result[position++] = box.rect.fTop;
-//     result[position++] = box.rect.fRight;
-//     result[position++] = box.rect.fBottom;
-//     result[position++] = static_cast<float>(box.direction);
-//   }
-// }
+  unsigned long position = 0;
+  for (unsigned long i = 0; i < boxes.size(); i++) {
+    const txt::Paragraph::TextBox& box = boxes[i];
+    result[position++] = box.rect.fLeft;
+    result[position++] = box.rect.fTop;
+    result[position++] = box.rect.fRight;
+    result[position++] = box.rect.fBottom;
+    result[position++] = static_cast<float>(box.direction);
+  }
+}
 
 Float32List Paragraph::getRectsForRange(unsigned start, unsigned end,
                                          unsigned boxHeightStyle,

engine/src/shell/gpu/gpu_surface_gl.cc

   {
     TRACE_EVENT0("uiwidgets", "SkCanvas::Flush");
     onscreen_surface_->getCanvas()->flush();
-    // onscreen_surface_->getContext()->submit(true);
   }
 
   if (!delegate_->GLContextPresent()) {

engine/src/shell/platform/unity/android/uiwidgets_system.h

   void printf_console(const char* log, ...) {
     va_list vl;
     va_start(vl, log);
+    // TODO: error in __android_log_vprint -> vsnprintf -> __vfprintf -> strlen_a
     // unity_uiwidgets_->printf_consolev(log, vl);
     va_end(vl);
   }

engine/src/shell/platform/unity/android/unity_surface_manager.cc

     FML_DCHECK(fbo_ != 0);
     glDeleteFramebuffers(1, &fbo_);
     fbo_ = 0;
-
-    // FML_DCHECK(fbo_texture_ != 0);
-    // glDeleteTextures(1, &fbo_texture_);
-    // fbo_texture_ = 0;
-
-    // FML_DCHECK(fbo_egl_image_ != nullptr);
-    // eglDestroyImageKHR(egl_display_, fbo_egl_image_);
-    // fbo_egl_image_ = nullptr;
   }
 
   bool UnitySurfaceManager::ClearCurrent()