Move early outs to the top of View::Paint and OnPaintLayer

This makes the CullSet check into an early out instead of
an if-block wrapping a whole function.

It also moves the |visible_| early out to the same place
from PaintCommon(). This hints at combining Paint() and
PaintCommont().

This also moves the |visible_| early out to the other caller
of PaintCommon() which is OnPaintLayer(), and can early
out before doing the solid color clear.

BUG=466426

Review URL: https://codereview.chromium.org/1037513002

Cr-Commit-Position: refs/heads/master@{#322220}

ui/views/view.cc

@@ -764,9 +764,13 @@ void View::SchedulePaintInRect(const gfx::Rect& rect) {
 }
 
 void View::Paint(gfx::Canvas* canvas, const CullSet& cull_set) {
+  if (!visible_)
+    return;
   // The cull_set may allow us to skip painting without canvas construction or
   // even canvas rect intersection.
-  if (cull_set.ShouldPaint(this)) {
+  if (!cull_set.ShouldPaint(this))
+    return;
+
   TRACE_EVENT1("views", "View::Paint", "class", GetClassName());
 
   gfx::ScopedCanvas scoped_canvas(canvas);
@@ -809,10 +813,9 @@ void View::Paint(gfx::Canvas* canvas, const CullSet& cull_set) {
 
     // Now query our bounds_tree_ for a set of damaged views that intersect
     // our canvas bounds.
-      scoped_ptr<base::hash_set<intptr_t> > damaged_views(
+    scoped_ptr<base::hash_set<intptr_t>> damaged_views(
         new base::hash_set<intptr_t>());
-      bounds_tree_->AppendIntersectingRecords(
-          canvas_bounds, damaged_views.get());
+    bounds_tree_->AppendIntersectingRecords(canvas_bounds, damaged_views.get());
     // Construct a CullSet to wrap the damaged views set, it will delete it
     // for us on scope exit.
     CullSet paint_root_cull_set(damaged_views.Pass());
@@ -822,7 +825,6 @@ void View::Paint(gfx::Canvas* canvas, const CullSet& cull_set) {
     // Not a paint root, so we can proceed as normal.
     PaintCommon(canvas, cull_set);
   }
-  }
 }
 
 void View::set_background(Background* b) {
@@ -1464,6 +1466,8 @@ void View::UpdateChildLayerBounds(const gfx::Vector2d& offset) {
 void View::OnPaintLayer(gfx::Canvas* canvas) {
   if (!layer() || !layer()->fills_bounds_opaquely())
     canvas->DrawColor(SK_ColorBLACK, SkXfermode::kClear_Mode);
+  if (!visible_)
+    return;
   PaintCommon(canvas, CullSet());
 }
 
@@ -1748,9 +1752,6 @@ void View::SchedulePaintBoundsChanged(SchedulePaintType type) {
 }
 
 void View::PaintCommon(gfx::Canvas* canvas, const CullSet& cull_set) {
-  if (!visible_)
-    return;
-
   {
     // If the View we are about to paint requested the canvas to be flipped, we
     // should change the transform appropriately.