DevTools: fix screenshot size when emulated viewport is smaller than root view

content/browser/devtools/devtools_frame_trace_recorder.cc

Index: content/browser/devtools/devtools_frame_trace_recorder.cc
diff --git a/content/browser/devtools/devtools_frame_trace_recorder.cc b/content/browser/devtools/devtools_frame_trace_recorder.cc
index 0771f8f1908760c01a442e5d321b112dd9a20e83..8d4696fcc533b803bb0eea1fa3e835c0ce77b2cb 100644
--- a/content/browser/devtools/devtools_frame_trace_recorder.cc
+++ b/content/browser/devtools/devtools_frame_trace_recorder.cc
@@ -91,14 +91,20 @@ void CaptureFrame(RenderFrameHostImpl* host,
   int current_frame_count = base::subtle::NoBarrier_Load(&frame_data_count);
   if (current_frame_count >= kMaximumFrameDataCount)
     return;
-  float scale = metadata.page_scale_factor;
-  float area = metadata.scrollable_viewport_size.GetArea();
-  if (area * scale * scale > kFrameAreaLimit)
-    scale = sqrt(kFrameAreaLimit / area);
-  gfx::Size snapshot_size(gfx::ToRoundedSize(gfx::ScaleSize(
-      metadata.scrollable_viewport_size, scale)));
+
+  gfx::Size src_size = gfx::ToCeiledSize(gfx::ScaleSize(
+      metadata.scrollable_viewport_size, metadata.page_scale_factor));
+  gfx::Size snapshot_size;
+  float area = src_size.GetArea();
+  if (area <= kFrameAreaLimit) {
+    snapshot_size = src_size;
+  } else {
+    double scale = sqrt(kFrameAreaLimit / area);
+    snapshot_size = gfx::ScaleToCeiledSize(src_size, scale);
+  }
+
   view->CopyFromCompositingSurface(
-      gfx::Rect(), snapshot_size,
+      gfx::Rect(gfx::Point(), src_size), snapshot_size,
       base::Bind(FrameCaptured, base::TimeTicks::Now()),
       kN32_SkColorType);
 }