Move the IsSupported* mime functions out of //net and into //components/mime_util

components/mime_util/mime_util.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/mime_util/mime_util.h"
+
+#include "base/containers/hash_tables.h"
+#include "base/lazy_instance.h"
+#include "base/strings/string_util.h"
+#include "build/build_config.h"
+
+namespace mime_util {
+
+namespace {
+
+// Dictionary of cryptographic file mime types.
+struct CertificateMimeTypeInfo {
+  const char* const mime_type;
+  net::CertificateMimeType cert_type;
+};
+
+const CertificateMimeTypeInfo kSupportedCertificateTypes[] = {
+    {"application/x-x509-user-cert", net::CERTIFICATE_MIME_TYPE_X509_USER_CERT},
+#if defined(OS_ANDROID)
+    {"application/x-x509-ca-cert", net::CERTIFICATE_MIME_TYPE_X509_CA_CERT},
+    {"application/x-pkcs12", net::CERTIFICATE_MIME_TYPE_PKCS12_ARCHIVE},
+#endif
+};
+
+// From WebKit's WebCore/platform/MIMETypeRegistry.cpp:
+
+const char* const kSupportedImageTypes[] = {"image/jpeg",
+                                            "image/pjpeg",
+                                            "image/jpg",
+                                            "image/webp",
+                                            "image/png",
+                                            "image/gif",
+                                            "image/bmp",
+                                            "image/vnd.microsoft.icon",  // ico
+                                            "image/x-icon",              // ico
+                                            "image/x-xbitmap",           // xbm
+                                            "image/x-png"};
+
+//  Mozilla 1.8 and WinIE 7 both accept text/javascript and text/ecmascript.
+//  Mozilla 1.8 accepts application/javascript, application/ecmascript, and
+// application/x-javascript, but WinIE 7 doesn't.
+//  WinIE 7 accepts text/javascript1.1 - text/javascript1.3, text/jscript, and
+// text/livescript, but Mozilla 1.8 doesn't.
+//  Mozilla 1.8 allows leading and trailing whitespace, but WinIE 7 doesn't.
+//  Mozilla 1.8 and WinIE 7 both accept the empty string, but neither accept a
+// whitespace-only string.
+//  We want to accept all the values that either of these browsers accept, but
+// not other values.
+const char* const kSupportedJavascriptTypes[] = {"text/javascript",
+                                                 "text/ecmascript",
+                                                 "application/javascript",
+                                                 "application/ecmascript",
+                                                 "application/x-javascript",
+                                                 "text/javascript1.1",
+                                                 "text/javascript1.2",
+                                                 "text/javascript1.3",
+                                                 "text/jscript",
+                                                 "text/livescript"};
+
+// These types are excluded from the logic that allows all text/ types because
+// while they are technically text, it's very unlikely that a user expects to
+// see them rendered in text form.
+static const char* const kUnsupportedTextTypes[] = {
+    "text/calendar",
+    "text/x-calendar",
+    "text/x-vcalendar",
+    "text/vcalendar",
+    "text/vcard",
+    "text/x-vcard",
+    "text/directory",
+    "text/ldif",
+    "text/qif",
+    "text/x-qif",
+    "text/x-csv",
+    "text/x-vcf",
+    "text/rtf",
+    "text/comma-separated-values",
+    "text/csv",
+    "text/tab-separated-values",
+    "text/tsv",
+    "text/ofx",                         // http://crbug.com/162238
+    "text/vnd.sun.j2me.app-descriptor"  // http://crbug.com/176450
+};
+
+// Note:
+// - does not include javascript types list (see supported_javascript_types)
+// - does not include types starting with "text/" (see
+//   IsSupportedNonImageMimeType())
+static const char* const kSupportedNonImageTypes[] = {
+    "image/svg+xml",  // SVG is text-based XML, even though it has an image/
+                      // type
+    "application/xml",
+    "application/atom+xml",
+    "application/rss+xml",
+    "application/xhtml+xml",
+    "application/json",
+    "multipart/related",  // For MHTML support.
+    "multipart/x-mixed-replace"
+    // Note: ADDING a new type here will probably render it AS HTML. This can
+    // result in cross site scripting.
+};
+
+// Singleton utility class for mime types
+class MimeUtil {
+ public:
+  bool IsSupportedImageMimeType(const std::string& mime_type) const;
+  bool IsSupportedNonImageMimeType(const std::string& mime_type) const;
+  bool IsUnsupportedTextMimeType(const std::string& mime_type) const;
+  bool IsSupportedJavascriptMimeType(const std::string& mime_type) const;
+
+  bool IsSupportedMimeType(const std::string& mime_type) const;
+
+ private:
+  friend struct base::DefaultLazyInstanceTraits<MimeUtil>;
+
+  using MimeMappings = base::hash_set<std::string>;

[asanka, 2015/04/29 00:14:06]

Minor nit: there are sets. Not maps.

(I know you are just moving code).

+
+  MimeUtil();
+
+  MimeMappings image_map_;
+  MimeMappings non_image_map_;
+  MimeMappings unsupported_text_map_;
+  MimeMappings javascript_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(MimeUtil);
+};
+
+MimeUtil::MimeUtil() {
+  // Initialize the supported non-image types.

[asanka, 2015/04/29 00:14:06]

Nit: remove.

+  for (size_t i = 0; i < arraysize(kSupportedNonImageTypes); ++i)
+    non_image_map_.insert(kSupportedNonImageTypes[i]);
+  for (size_t i = 0; i < arraysize(kSupportedImageTypes); ++i)
+    image_map_.insert(kSupportedImageTypes[i]);
+  for (size_t i = 0; i < arraysize(kUnsupportedTextTypes); ++i)
+    unsupported_text_map_.insert(kUnsupportedTextTypes[i]);
+  for (size_t i = 0; i < arraysize(kSupportedJavascriptTypes); ++i) {
+    javascript_map_.insert(kSupportedJavascriptTypes[i]);
+    non_image_map_.insert(kSupportedJavascriptTypes[i]);
+  }
+  for (size_t i = 0; i < arraysize(kSupportedCertificateTypes); ++i)
+    non_image_map_.insert(kSupportedCertificateTypes[i].mime_type);
+}
+
+bool MimeUtil::IsSupportedImageMimeType(const std::string& mime_type) const {
+  return image_map_.find(base::StringToLowerASCII(mime_type)) !=
+         image_map_.end();
+}
+
+bool MimeUtil::IsSupportedNonImageMimeType(const std::string& mime_type) const {
+  return non_image_map_.find(base::StringToLowerASCII(mime_type)) !=
+             non_image_map_.end() ||
+         (StartsWithASCII(mime_type, "text/", false /* case insensitive */) &&
+          !IsUnsupportedTextMimeType(mime_type)) ||
+         (StartsWithASCII(mime_type, "application/", false) &&
+          net::MatchesMimeType("application/*+json", mime_type)) ||
+         net::IsSupportedMediaMimeType(mime_type);
+}
+
+bool MimeUtil::IsUnsupportedTextMimeType(const std::string& mime_type) const {
+  return unsupported_text_map_.find(base::StringToLowerASCII(mime_type)) !=
+         unsupported_text_map_.end();
+}
+
+bool MimeUtil::IsSupportedJavascriptMimeType(
+    const std::string& mime_type) const {
+  return javascript_map_.find(mime_type) != javascript_map_.end();
+}
+
+// Mirrors WebViewImpl::CanShowMIMEType()

[asanka, 2015/04/29 00:14:06]

Nit: Comment appears to have bitrotted. 

+bool MimeUtil::IsSupportedMimeType(const std::string& mime_type) const {
+  return (StartsWithASCII(mime_type, "image/", false) &&
+          IsSupportedImageMimeType(mime_type)) ||
+         IsSupportedNonImageMimeType(mime_type);
+}
+
+// This variable is Leaky because it is accessed from WorkerPool threads.
+static base::LazyInstance<MimeUtil>::Leaky g_mime_util =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+bool IsSupportedImageMimeType(const std::string& mime_type) {
+  return g_mime_util.Get().IsSupportedImageMimeType(mime_type);
+}
+
+bool IsSupportedNonImageMimeType(const std::string& mime_type) {
+  return g_mime_util.Get().IsSupportedNonImageMimeType(mime_type);
+}
+
+bool IsUnsupportedTextMimeType(const std::string& mime_type) {
+  return g_mime_util.Get().IsUnsupportedTextMimeType(mime_type);
+}
+
+bool IsSupportedJavascriptMimeType(const std::string& mime_type) {
+  return g_mime_util.Get().IsSupportedJavascriptMimeType(mime_type);
+}
+
+bool IsSupportedCertificateMimeType(const std::string& mime_type) {
+  net::CertificateMimeType file_type =
+      GetCertificateMimeTypeForMimeType(mime_type);
+  return file_type != net::CERTIFICATE_MIME_TYPE_UNKNOWN;
+}
+
+bool IsSupportedMimeType(const std::string& mime_type) {
+  return g_mime_util.Get().IsSupportedMimeType(mime_type);
+}
+
+net::CertificateMimeType GetCertificateMimeTypeForMimeType(
+    const std::string& mime_type) {
+  // Don't create a map, there is only one entry in the table,
+  // except on Android.
+  for (size_t i = 0; i < arraysize(kSupportedCertificateTypes); ++i) {
+    if (base::strcasecmp(mime_type.c_str(),
+                         kSupportedCertificateTypes[i].mime_type) == 0) {
+      return kSupportedCertificateTypes[i].cert_type;
+    }
+  }
+
+  return net::CERTIFICATE_MIME_TYPE_UNKNOWN;
+}
+
+}  // namespace mime_util