Add support for refreshing contents of providers which don't support watchers.

chrome/common/extensions/api/file_system_provider_capabilities/file_system_provider_capabilities_handler.h

 // Copyright 2015 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.
 
 #ifndef CHROME_COMMON_EXTENSIONS_API_FILE_SYSTEM_PROVIDER_CAPABILITIES_FILE_SYSTEM_PROVIDER_CAPABILITIES_HANDLER_H_
 #define CHROME_COMMON_EXTENSIONS_API_FILE_SYSTEM_PROVIDER_CAPABILITIES_FILE_SYSTEM_PROVIDER_CAPABILITIES_HANDLER_H_
 
 #include <string>
 #include <vector>
 
 #include "chrome/common/extensions/api/file_system_provider.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/manifest_handler.h"
 
 namespace extensions {
 
 // Source of provider file systems.
 enum FileSystemProviderSource { SOURCE_FILE, SOURCE_NETWORK, SOURCE_DEVICE };
 
 // Represents capabilities of a file system provider.
 class FileSystemProviderCapabilities : public Extension::ManifestData {
  public:
   FileSystemProviderCapabilities();
   FileSystemProviderCapabilities(bool configurable,
+                                 bool watchable,
                                  bool multiple_mounts,
                                  FileSystemProviderSource source);
   ~FileSystemProviderCapabilities() override;
 
   // Returns capabilities of a providing |extension| if declared in the
   // manifets. Otherwise NULL.
   static const FileSystemProviderCapabilities* Get(const Extension* extension);
 
   bool configurable() const { return configurable_; }
+  bool watchable() const { return watchable_; }
   bool multiple_mounts() const { return multiple_mounts_; }
   FileSystemProviderSource source() const { return source_; }
 
  private:
   bool configurable_;
+  bool watchable_;
   bool multiple_mounts_;
   FileSystemProviderSource source_;
 };
 
 // Parses the "file_system_provider_capabilities" manifest key.
 class FileSystemProviderCapabilitiesHandler : public ManifestHandler {
  public:
   FileSystemProviderCapabilitiesHandler();
   ~FileSystemProviderCapabilitiesHandler() override;
 
   // ManifestHandler overrides.
   bool Parse(Extension* extension, base::string16* error) override;
   bool AlwaysParseForType(Manifest::Type type) const override;
 
  private:
   const std::vector<std::string> Keys() const override;
 
   DISALLOW_COPY_AND_ASSIGN(FileSystemProviderCapabilitiesHandler);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_API_FILE_SYSTEM_PROVIDER_CAPABILITIES_FILE_SYSTEM_PROVIDER_CAPABILITIES_HANDLER_H_