fix unpack the same icon twice

Extension unpacker may process the icon twice when icon path presents in
an extension manifest twice as different string values, for example:
./icons/myicon.jpg and icons/myicon.jpg.

Bug: 
Change-Id: Ie6d334510b94ee78217aade6906a7c5139b6f204
Reviewed-on: https://chromium-review.googlesource.com/836047
Commit-Queue: Finnur Thorarinsson <finnur@chromium.org>
Reviewed-by: Finnur Thorarinsson <finnur@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526176}

extensions/common/extension_icon_set.cc

@@ -4,10 +4,41 @@
 
 #include "extensions/common/extension_icon_set.h"
 
+#include <vector>
+
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 
+namespace {
+
+// Normalize relative path that does not reference to parent directory. Removes
+// ".". Returns false if path can not be normalized, i.e. it references parent
+// or empty after normalization.
+bool NormalizeRelativePath(const base::FilePath& path, base::FilePath* result) {
+  DCHECK(result);
+
+  if (path.ReferencesParent())
+    return false;
+
+  std::vector<base::FilePath::StringType> components;
+  path.GetComponents(&components);
+
+  base::FilePath rv;
+  for (const auto& path_component : components) {
+    if (path_component != base::FilePath::kCurrentDirectory)
+      rv = rv.Append(path_component);
+  }
+
+  if (rv.empty())
+    return false;
+
+  *result = std::move(rv);
+  return true;
+}
+
+}  // namespace
+
 ExtensionIconSet::ExtensionIconSet() {}
 
 ExtensionIconSet::ExtensionIconSet(const ExtensionIconSet& other) = default;
@@ -75,6 +106,11 @@ int ExtensionIconSet::GetIconSizeFromPath(base::StringPiece path) const {
 
 void ExtensionIconSet::GetPaths(std::set<base::FilePath>* paths) const {
   CHECK(paths);
-  for (auto iter : map())
-    paths->insert(base::FilePath::FromUTF8Unsafe(iter.second));
+  for (const auto& iter : map()) {
+    base::FilePath normalized_path;
+    if (NormalizeRelativePath(base::FilePath::FromUTF8Unsafe(iter.second),
+                              &normalized_path)) {
+      paths->emplace(std::move(normalized_path));
+    }
+  }
 }

extensions/common/extension_icon_set.h

@@ -44,7 +44,7 @@ class ExtensionIconSet {
   void Add(int size, const std::string& path);
 
   // Gets path value of the icon found when searching for |size| using
-  // |mathc_type|.
+  // |match_type|.
   const std::string& Get(int size, MatchType match_type) const;
 
   // Returns true iff the set contains the specified path.

extensions/common/extension_icon_set_unittest.cc

@@ -90,4 +90,31 @@ TEST(ExtensionIconSetTest, FindSize) {
             icons.GetIconSizeFromPath("foo"));
 }
 
+TEST(ExtensionIconSetTest, CollapsesSameRelativePaths) {
+  ExtensionIconSet icons;
+  icons.Add(extension_misc::EXTENSION_ICON_BITTY, "foo/icon.jpg");
+  icons.Add(extension_misc::EXTENSION_ICON_SMALL, "./foo/icon.jpg");
+  icons.Add(extension_misc::EXTENSION_ICON_LARGE, "./bar/../foo/icon.jpg");
+
+  std::set<base::FilePath> paths;
+  icons.GetPaths(&paths);
+
+  const std::set<base::FilePath> expected_paths = {
+      base::FilePath::FromUTF8Unsafe("foo").AppendASCII("icon.jpg")};
+  EXPECT_EQ(expected_paths, paths);
+}
+
+TEST(ExtensionIconSetTest, IgnoresIncorrectRelativePaths) {
+  ExtensionIconSet icons;
+  icons.Add(extension_misc::EXTENSION_ICON_BITTY, "foo/../../icon.jpg");
+  icons.Add(extension_misc::EXTENSION_ICON_SMALL, "../icon.jpg");
+  icons.Add(extension_misc::EXTENSION_ICON_LARGE, "./foo/icons/../..");
+  icons.Add(extension_misc::EXTENSION_ICON_GIGANTOR, "./foo/../..");
+
+  std::set<base::FilePath> paths;
+  icons.GetPaths(&paths);
+
+  EXPECT_TRUE(paths.empty());
+}
+
 }  // namespace