Don't return unsupported scales frrom GetScaleFactorFromScale()

ui/base/layout.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/base/layout.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 
@@ skipping 70 matching lines @@
         supported_scale_factors->push_back(ui::SCALE_FACTOR_140P);
         supported_scale_factors->push_back(ui::SCALE_FACTOR_180P);
       }
 #elif defined(USE_ASH)
       supported_scale_factors->push_back(ui::SCALE_FACTOR_200P);
 #endif
   }
   return *supported_scale_factors;
 }
 
+ui::ScaleFactor GetScaleFactorFromScaleInternal(float scale,
+                                                bool includeUnsupported) {

[pkotwicz, 2012/09/19 14:22:10]

Nit: use camel case for variable include_unsupported

+  size_t closest_match = 0;
+  float smallest_diff =  std::numeric_limits<float>::max();
+  for (size_t i = 0; i < kScaleFactorScalesLength; ++i) {
+    if (!includeUnsupported &&
+        !ui::IsScaleFactorSupported(static_cast<ui::ScaleFactor>(i)))
+      continue;
+    float diff = std::abs(kScaleFactorScales[i] - scale);
+    if (diff < smallest_diff) {
+      closest_match = i;
+      smallest_diff = diff;
+    }
+  }
+  return static_cast<ui::ScaleFactor>(closest_match);
+}
+
 }  // namespace
 
 namespace ui {
 
 // Note that this function should be extended to select
 // LAYOUT_TOUCH when appropriate on more platforms than just
 // Windows and Ash.
 DisplayLayout GetDisplayLayout() {
 #if defined(USE_ASH)
   if (UseTouchOptimizedUI())
     return LAYOUT_TOUCH;
   return LAYOUT_ASH;
 #elif defined(OS_WIN)
   if (UseTouchOptimizedUI())
     return LAYOUT_TOUCH;
   return LAYOUT_DESKTOP;
 #else
   return LAYOUT_DESKTOP;
 #endif
 }
 
 ScaleFactor GetScaleFactorFromScale(float scale) {
-  size_t closest_match = 0;
-  float smallest_diff =  std::numeric_limits<float>::max();
-  for (size_t i = 0; i < kScaleFactorScalesLength; ++i) {
-    float diff = std::abs(kScaleFactorScales[i] - scale);
-    if (diff < smallest_diff) {
-      closest_match = i;
-      smallest_diff = diff;
-    }
-  }
-  return static_cast<ui::ScaleFactor>(closest_match);
+  return GetScaleFactorFromScaleInternal(scale, true);
+}
+
+ScaleFactor GetSupportedScaleFactorFromScale(float scale) {
+  return GetScaleFactorFromScaleInternal(scale, false);
 }
 
 float GetScaleFactorScale(ScaleFactor scale_factor) {
   return kScaleFactorScales[scale_factor];
 }
 
 std::vector<ScaleFactor> GetSupportedScaleFactors() {
   return GetSupportedScaleFactorsInternal();
 }
 
@@ skipping 24 matching lines @@
   return GetScaleFactorFromScale(
       root_window->compositor()->device_scale_factor());
 #else
   NOTIMPLEMENTED();
   return SCALE_FACTOR_NONE;
 #endif
 }
 #endif  // !defined(OS_MACOSX)
 
 }  // namespace ui