Improve keying for theme caches, rebase system theme on config change

Themes now use an array of applied styles rather than a String to store
their history. They are keyed based on a hash code computed from the
history of applied styles. The themed drawable cache has been abstracted
out into its own class.

Also updates system context to use DayNight as the default and ensures
that GlobalActions uses the correct context, which exercises the change.

CTS tests have been added in another CL.

Bug: 20421157
Change-Id: I9eb4b7dffd198ad24d02f656eaf0839570b59caa

1 files changed, 8 insertions, 0 deletions

diff --git a/core/jni/android_util_AssetManager.cpp b/core/jni/android_util_AssetManager.cpp
index db495dd..74a9e4e 100644
--- a/core/jni/android_util_AssetManager.cpp
+++ b/core/jni/android_util_AssetManager.cpp
@@ -976,6 +976,12 @@ static void android_content_AssetManager_copyTheme(JNIEnv* env, jobject clazz,
     dest->setTo(*src);
 }
 
+static void android_content_AssetManager_clearTheme(JNIEnv* env, jobject clazz, jlong themeHandle)
+{
+    ResTable::Theme* theme = reinterpret_cast<ResTable::Theme*>(themeHandle);
+    theme->clear();
+}
+
 static jint android_content_AssetManager_loadThemeAttributeValue(
     JNIEnv* env, jobject clazz, jlong themeHandle, jint ident, jobject outValue, jboolean resolve)
 {
@@ -2108,6 +2114,8 @@ static JNINativeMethod gAssetManagerMethods[] = {
         (void*) android_content_AssetManager_applyThemeStyle },
     { "copyTheme", "(JJ)V",
         (void*) android_content_AssetManager_copyTheme },
+    { "clearTheme", "(J)V",
+        (void*) android_content_AssetManager_clearTheme },
     { "loadThemeAttributeValue", "(JILandroid/util/TypedValue;Z)I",
         (void*) android_content_AssetManager_loadThemeAttributeValue },
     { "getThemeChangingConfigurations", "(J)I",