Support for json media types as (non-image) mime types.

LayoutTests/http/tests/inspector/network/json-preview-expected.txt

Index: LayoutTests/http/tests/inspector/network/json-preview-expected.txt
diff --git a/LayoutTests/http/tests/inspector/network/json-preview-expected.txt b/LayoutTests/http/tests/inspector/network/json-preview-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..28106dc24c798aea6b976915e97561a36b1503b6
--- /dev/null
+++ b/LayoutTests/http/tests/inspector/network/json-preview-expected.txt
@@ -0,0 +1,33 @@
+CONSOLE MESSAGE: line 6: XHR loaded: 1
+CONSOLE MESSAGE: line 6: XHR loaded: 2
+Tests that resources with JSON MIME types are previewed with the JSON viewer.
+
+
+Running: test1
+request.url: http://127.0.0.1:8000/inspector/network/resources/json.php?type=application%2Fjson
+request.type: xhr
+request.mimeType: application/json
+resource.content: {"number": "42"}
+
+Request previewer is JSON: true
+request.url: http://127.0.0.1:8000/inspector/network/resources/json.php?type=application%2Fjson
+request.type: document
+request.mimeType: application/json
+resource.content: {"number": "42"}
+
+Request previewer is JSON: true
+
+Running: test2
+request.url: http://127.0.0.1:8000/inspector/network/resources/json.php?type=application%2Fvnd.document%2Bjson
+request.type: xhr
+request.mimeType: application/vnd.document+json
+resource.content: {"number": "42"}
+
+Request previewer is JSON: true
+request.url: http://127.0.0.1:8000/inspector/network/resources/json.php?type=application%2Fvnd.document%2Bjson
+request.type: document
+request.mimeType: application/vnd.document+json
+resource.content: {"number": "42"}
+
+Request previewer is JSON: true
+