Add dawn version hash to cache keys.

Motivation is to simplify cache evicting by reusing the LRU to evict stale entries from older Dawn versions since there isn't already a simple cache busting solution. The dawn version will just be pushed into the cache keys instead so old version entries will eventually be retired.

- Removes the fingerprint from the GetCachingInterface API on DawnNative.
- Adds the "fingerprint", which was just the hash, to the device;s cache key directly instead.

Bug: dawn:549
Change-Id: I573aa03a2bb96dfe044293b1176d3a7746725572
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/94140
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Loko Kung <lokokung@google.com>

include/dawn/platform/DawnPlatform.h

@@ -93,10 +93,10 @@ class DAWN_PLATFORM_EXPORT Platform {
                                    const uint64_t* argValues,
                                    unsigned char flags);
 
-    // The |fingerprint| is provided by Dawn to inform the client to discard the Dawn caches
-    // when the fingerprint changes. The returned CachingInterface is expected to outlive the
-    // device which uses it to persistently cache objects.
-    virtual CachingInterface* GetCachingInterface(const void* fingerprint, size_t fingerprintSize);
+    // The returned CachingInterface is expected to outlive the device which uses it to persistently
+    // cache objects.
+    virtual CachingInterface* GetCachingInterface();
+
     virtual std::unique_ptr<WorkerTaskPool> CreateWorkerTaskPool();
 
   private: