deep_memory_profiler: Replace 'WebCore' with 'blink'.

tools/deep_memory_profiler/policy.l1.json

 {
   "components": [
     "second",
     "mmap-profiler",
     "mmap-type-profiler",
     "mmap-tcmalloc",
     "FROM_HERE_FOR_TOTAL",
     "mustbezero",
     "unhooked-absent",
     "unhooked-anonymous",
@@ skipping 123 matching lines @@
       "stacktrace": ".*v8::.*",
       "allocator": "malloc"
     },
     {
       "name": "tc-skia",
       "stacktrace": ".*Sk[A-Za-z_]+::.*",
       "allocator": "malloc"
     },
     {
       "name": "tc-webkit-catch-all",
-      "stacktrace": ".*(WTF::|WebCore::|WebKit::).*",
+      "stacktrace": ".*(WTF::|blink::|WebKit::).*",
       "allocator": "malloc"
     },
     {
       "name": "tc-unknown-string",
       "stacktrace": ".*std::basic_string::_Rep::_S_create.*",
       "allocator": "malloc"
     },
     {
       "name": "tc-catch-all",
       "stacktrace": ".*",
@@ skipping 40 matching lines @@
       "allocator": "optional"
     },
     {
       "name": "other",
       "stacktrace": "optional",
       "allocator": "optional"
     }
   ],
   "version": "POLICY_DEEP_3"
 }