Add UMA for testing whether the Chromium library was page aligned in the APK file.

third_party/android_crazy_linker/src/src/crazy_linker_library_list.cpp

Index: third_party/android_crazy_linker/src/src/crazy_linker_library_list.cpp
diff --git a/third_party/android_crazy_linker/src/src/crazy_linker_library_list.cpp b/third_party/android_crazy_linker/src/src/crazy_linker_library_list.cpp
index 1ca932109ddcbed447c11be7dfde8ccbf0764143..99cc02e81bf7d2b7a6c4e193c1168bb8ad1d5e9e 100644
--- a/third_party/android_crazy_linker/src/src/crazy_linker_library_list.cpp
+++ b/third_party/android_crazy_linker/src/src/crazy_linker_library_list.cpp
@@ -392,15 +392,33 @@ LibraryView* LibraryList::LoadLibrary(const char* lib_name,
 #error "Unsupported target abi"
 #endif
 
-const size_t kMaxFilenameInZip = 256;
-const size_t kPageSize = 4096;
-
 LibraryView* LibraryList::LoadLibraryInZipFile(const char* zip_file_path,
                                                const char* lib_name,
                                                int dlopen_flags,
                                                uintptr_t load_address,
                                                SearchPathList* search_path_list,
                                                Error* error) {
+  int offset = FindAlignedLibraryInZipFile(zip_file_path, lib_name, error);
+  if (offset == -1) {
+    return NULL;
+  }
+
+  return LoadLibrary(
+      zip_file_path, dlopen_flags, load_address, offset,
+      search_path_list, error);
+}
+
+void LibraryList::AddLibrary(LibraryView* wrap) {
+  known_libraries_.PushBack(wrap);
+}
+
+const size_t kMaxFilenameInZip = 256;
+const size_t kPageSize = 4096;
+
+int LibraryList::FindAlignedLibraryInZipFile(
+    const char* zip_file_path,
+    const char* lib_name,
+    Error* error) {
   String fullname;
   fullname.Reserve(kMaxFilenameInZip);
   fullname = "lib/";
@@ -409,29 +427,27 @@ LibraryView* LibraryList::LoadLibraryInZipFile(const char* zip_file_path,
   fullname += lib_name;
 
   if (fullname.size() + 1 > kMaxFilenameInZip) {
-    error->Format("Filename too long for a file in a zip file %s\n",
-                  fullname.c_str());
-    return NULL;
+    if (error) {
+      error->Format("Filename too long for a file in a zip file %s\n",
+                    fullname.c_str());
+    }
+    return -1;
   }

[picksi1, 2014/10/28 11:37:09]

Instead of returning -1 can we return a constant (e.g.) UNLOADABLE and also
check for this at the call site(s). You should probably also assert  that the
'correct' result (i.e. offset) doesn't equal UNLOADABLE, in case someone fiddles
with this code later on.

[petrcermak, 2014/10/28 12:16:48]

Done.

 
   int offset = FindStartOffsetOfFileInZipFile(zip_file_path, fullname.c_str());
   if (offset == -1) {
-    return NULL;
+    return -1;
   }
 
   if ((offset & (kPageSize - 1)) != 0) {

[picksi1, 2014/10/28 11:37:08]

nit: This only works because kPageSize is a power of 2, is it worth adding a
build time assert (if such a thing exists in this code base) to confirm this is
the case, e.g. ASSERT( (kPageSize & (kPageSize-1)) == 0 )?

[petrcermak, 2014/10/28 12:16:48]

Done (using C++11 static_assert).

-    error->Format("Library %s is not page aligned in zipfile %s\n",
-                  lib_name, zip_file_path);
-    return NULL;
+    if (error) {
+      error->Format("Library %s is not page aligned in zipfile %s\n",
+                    lib_name, zip_file_path);
+    }
+    return -1;
   }
 
-  return LoadLibrary(
-      zip_file_path, dlopen_flags, load_address, offset,
-      search_path_list, error);
-}
-
-void LibraryList::AddLibrary(LibraryView* wrap) {
-  known_libraries_.PushBack(wrap);
+  return offset;
 }
 
 LibraryView* LibraryList::FindKnownLibrary(const char* name) {