Removes device from load/store in caching interface.

- No longer needed since the device information should be stored in the cache key.

Bug: dawn:549
Change-Id: I7c4e31e61df93ba317bc6eeb6a84074585f7eed2
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/88365
Reviewed-by: Austin Eng <enga@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Shrek Shao <shrekshao@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>

include/dawn/platform/DawnPlatform.h

@@ -42,15 +42,10 @@ class DAWN_PLATFORM_EXPORT CachingInterface {
     // size returned. The second mode is used to query for the existence of
     // the |key| where |valueOut| is nullptr and |valueSize| must be 0.
     // The return size is non-zero if the |key| exists.
-    virtual size_t LoadData(const WGPUDevice device,
-                            const void* key,
-                            size_t keySize,
-                            void* valueOut,
-                            size_t valueSize) = 0;
+    virtual size_t LoadData(const void* key, size_t keySize, void* valueOut, size_t valueSize) = 0;
 
     // StoreData puts a |value| in the cache which corresponds to the |key|.
-    virtual void StoreData(const WGPUDevice device,
-                           const void* key,
+    virtual void StoreData(const void* key,
                            size_t keySize,
                            const void* value,
                            size_t valueSize) = 0;