Revert 55450 - Fix CheckFalseTest.CheckFails on Linux after my change to ui_test.

This makes PathService clear its cache after overriding a path.
We have many paths depending on each other, so this is necessary
to avoid inconsistencies.

Added a comment that PathService::Override should not be called
by production code.

TEST=ui_tests in Release mode
BUG=49838

Review URL: http://codereview.chromium.org/2805100

TBR=phajdan.jr@chromium.org
Review URL: http://codereview.chromium.org/3107001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55468 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 15 insertions, 27 deletions

diff --git a/base/path_service.cc b/base/path_service.cc
index 7b3b297..e363fe6 100644
--- a/base/path_service.cc
+++ b/base/path_service.cc
@@ -32,6 +32,7 @@ namespace base {
 namespace {
 
 typedef base::hash_map<int, FilePath> PathMap;
+typedef base::hash_set<int> PathSet;
 
 // We keep a linked list of providers.  In a debug build we ensure that no two
 // providers claim overlapping keys.
@@ -94,8 +95,8 @@ static Provider base_provider_posix = {
 
 struct PathData {
   Lock      lock;
-  PathMap   cache;      // Cache mappings from path key to path value.
-  PathMap   overrides;  // Track path overrides.
+  PathMap   cache;      // Track mappings from path key to path value.
+  PathSet   overrides;  // Track whether a path has been overridden.
   Provider* providers;  // Linked list of path service providers.
 
   PathData() {
@@ -141,20 +142,6 @@ bool PathService::GetFromCache(int key, FilePath* result) {
 }
 
 // static
-bool PathService::GetFromOverrides(int key, FilePath* result) {
-  PathData* path_data = GetPathData();
-  AutoLock scoped_lock(path_data->lock);
-
-  // check for an overriden version.
-  PathMap::const_iterator it = path_data->overrides.find(key);
-  if (it != path_data->overrides.end()) {
-    *result = it->second;
-    return true;
-  }
-  return false;
-}
-
-// static
 void PathService::AddToCache(int key, const FilePath& path) {
   PathData* path_data = GetPathData();
   AutoLock scoped_lock(path_data->lock);
@@ -179,9 +166,6 @@ bool PathService::Get(int key, FilePath* result) {
   if (GetFromCache(key, result))
     return true;
 
-  if (GetFromOverrides(key, result))
-    return true;
-
   FilePath path;
 
   // search providers for the requested path
@@ -216,6 +200,14 @@ bool PathService::Get(int key, std::wstring* result) {
 }
 #endif
 
+bool PathService::IsOverridden(int key) {
+  PathData* path_data = GetPathData();
+  DCHECK(path_data);
+
+  AutoLock scoped_lock(path_data->lock);
+  return path_data->overrides.find(key) != path_data->overrides.end();
+}
+
 bool PathService::Override(int key, const FilePath& path) {
   PathData* path_data = GetPathData();
   DCHECK(path_data);
@@ -237,14 +229,8 @@ bool PathService::Override(int key, const FilePath& path) {
     return false;
 
   AutoLock scoped_lock(path_data->lock);
-
-  // Clear the cache now. Some of its entries could have depended
-  // on the value we are overriding, and are now out of sync with reality.
-  path_data->cache.clear();
-
   path_data->cache[key] = file_path;
-  path_data->overrides[key] = file_path;
-
+  path_data->overrides.insert(key);
   return true;
 }
 
diff --git a/base/path_service.h b/base/path_service.h
index 4d99cdc..2b59247 100644
--- a/base/path_service.h
+++ b/base/path_service.h
@@ -45,6 +45,9 @@ class PathService {
   // over the lifetime of the app, so this method should be used with caution.
   static bool Override(int key, const FilePath& path);
 
+  // Return whether a path was overridden.
+  static bool IsOverridden(int key);
+
   // To extend the set of supported keys, you can register a path provider,
   // which is just a function mirroring PathService::Get.  The ProviderFunc
   // returns false if it cannot provide a non-empty path for the given key.
@@ -62,7 +65,6 @@ class PathService {
                                int key_end);
  private:
   static bool GetFromCache(int key, FilePath* path);
-  static bool GetFromOverrides(int key, FilePath* path);
   static void AddToCache(int key, const FilePath& path);
 };