Font Settings Extension API: Add functions to clear prefs.

chrome/browser/extensions/extension_font_settings_api.h

Index: chrome/browser/extensions/extension_font_settings_api.h
diff --git a/chrome/browser/extensions/extension_font_settings_api.h b/chrome/browser/extensions/extension_font_settings_api.h
index 5003c0b833cf8a03f6fb82d02eba9e907bb939cc..d60d20537981d27f3b50c79cdacfafbd56ba5519 100644
--- a/chrome/browser/extensions/extension_font_settings_api.h
+++ b/chrome/browser/extensions/extension_font_settings_api.h
@@ -56,6 +56,12 @@ class ExtensionFontSettingsEventRouter : public content::NotificationObserver {
   DISALLOW_COPY_AND_ASSIGN(ExtensionFontSettingsEventRouter);
 };
 
+class ClearFontFunction : public SyncExtensionFunction {
+ public:
+  virtual bool RunImpl() OVERRIDE;
+  DECLARE_EXTENSION_FUNCTION_NAME("experimental.fontSettings.clearFont")
+};
+
 class GetFontFunction : public SyncExtensionFunction {
  public:
   virtual bool RunImpl() OVERRIDE;
@@ -78,6 +84,16 @@ class GetFontListFunction : public AsyncExtensionFunction {
   bool CopyFontsToResult(base::ListValue* fonts);
 };
 
+// Base class for functions that clear a font pref.
+class ClearFontPrefExtensionFunction : public SyncExtensionFunction {
+ protected:
+  virtual bool RunImpl() OVERRIDE;
+
+  // Implementations should return the name of the preference to clear, like
+  // "webkit.webprefs.default_font_size".
+  virtual const char* GetPrefName() = 0;
+};
+
 // Base class for functions that get a font pref.
 class GetFontPrefExtensionFunction : public SyncExtensionFunction {
  protected:
@@ -106,6 +122,15 @@ class SetFontPrefExtensionFunction : public SyncExtensionFunction {
   virtual const char* GetKey() = 0;
 };
 
+class ClearDefaultFontSizeFunction : public ClearFontPrefExtensionFunction {
+ public:
+  DECLARE_EXTENSION_FUNCTION_NAME(
+      "experimental.fontSettings.clearDefaultFontSize")
+
+ protected:
+  virtual const char* GetPrefName() OVERRIDE;
+};
+
 class GetDefaultFontSizeFunction : public GetFontPrefExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION_NAME(
@@ -126,6 +151,16 @@ class SetDefaultFontSizeFunction : public SetFontPrefExtensionFunction {
   virtual const char* GetKey() OVERRIDE;
 };
 
+class ClearDefaultFixedFontSizeFunction
+    : public ClearFontPrefExtensionFunction {
+ public:
+  DECLARE_EXTENSION_FUNCTION_NAME(
+      "experimental.fontSettings.clearDefaultFixedFontSize")
+
+ protected:
+  virtual const char* GetPrefName() OVERRIDE;
+};
+
 class GetDefaultFixedFontSizeFunction : public GetFontPrefExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION_NAME(
@@ -146,6 +181,15 @@ class SetDefaultFixedFontSizeFunction : public SetFontPrefExtensionFunction {
   virtual const char* GetKey() OVERRIDE;
 };
 
+class ClearMinimumFontSizeFunction : public ClearFontPrefExtensionFunction {
+ public:
+  DECLARE_EXTENSION_FUNCTION_NAME(
+      "experimental.fontSettings.clearMinimumFontSize")
+
+ protected:
+  virtual const char* GetPrefName() OVERRIDE;
+};
+
 class GetMinimumFontSizeFunction : public GetFontPrefExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION_NAME(
@@ -166,6 +210,15 @@ class SetMinimumFontSizeFunction : public SetFontPrefExtensionFunction {
   virtual const char* GetKey() OVERRIDE;
 };
 
+class ClearDefaultCharacterSetFunction : public ClearFontPrefExtensionFunction {
+ public:
+  DECLARE_EXTENSION_FUNCTION_NAME(
+      "experimental.fontSettings.clearDefaultCharacterSet")
+
+ protected:
+  virtual const char* GetPrefName() OVERRIDE;
+};
+
 class GetDefaultCharacterSetFunction : public GetFontPrefExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION_NAME(