Add cache validation to ensure the validity

Create cache identity from GL_VERSION and store in ShaderCache.
In the next time ShaderCache is restored from disk, compare the
cache identity to ensure its validity. If GL_VERSION changes in
between, flush out entire FileBlobCache and start from an empty
one.

Bug: b/71800782
Test: Wrote a new unit test to save and restore ShaderCache
Test: hwui_unit_tests
Change-Id: Ie573dc4f18733eee090725be30445d879765231b
diff --git a/libs/hwui/renderthread/RenderThread.cpp b/libs/hwui/renderthread/RenderThread.cpp
index c1284ec..36ffaee 100644
--- a/libs/hwui/renderthread/RenderThread.cpp
+++ b/libs/hwui/renderthread/RenderThread.cpp
@@ -191,7 +191,9 @@
     GrContextOptions options;
     options.fPreferExternalImagesOverES3 = true;
     options.fDisableDistanceFieldPaths = true;
-    cacheManager().configureContext(&options);
+    auto glesVersion = reinterpret_cast<const char*>(glGetString(GL_VERSION));
+    auto size = glesVersion ? strlen(glesVersion) : -1;
+    cacheManager().configureContext(&options, glesVersion, size);
     sk_sp<GrContext> grContext(GrContext::MakeGL(std::move(glInterface), options));
     LOG_ALWAYS_FATAL_IF(!grContext.get());
     setGrContext(grContext);