Add UMA for measuring Content-Dispostion header use and abuse.

content/browser/download/download_stats.cc

Index: content/browser/download/download_stats.cc
diff --git a/content/browser/download/download_stats.cc b/content/browser/download/download_stats.cc
index 2da505a27a00e85e61d46f28f4c2995e71b8d3ce..cad6cbe4bac245454522b354b6c6a05f10a2bbcb 100644
--- a/content/browser/download/download_stats.cc
+++ b/content/browser/download/download_stats.cc
@@ -8,9 +8,12 @@
 #include "base/string_util.h"
 #include "content/browser/download/download_resource_handler.h"
 #include "content/public/browser/download_interrupt_reasons.h"
+#include "net/http/http_content_disposition.h"
 
 namespace content {
 
+namespace {
+
 // All possible error codes from the network module. Note that the error codes
 // are all positive (since histograms expect positive sample values).
 const int kAllInterruptReasonCodes[] = {
@@ -19,6 +22,52 @@ const int kAllInterruptReasonCodes[] = {
 #undef INTERRUPT_REASON
 };
 
+// These values are based on net::HttpContentDisposition::ParseResult values.
+// Values other than HEADER_PRESENT and IS_VALID are only measured if |IS_VALID|
+// is true.
+enum ContentDispositionCountTypes {
+  // Count of downloads which had a Content-Disposition headers. The total
+  // number of downloads is measured by UNTHROTTLED_COUNT.
+  CONTENT_DISPOSITION_HEADER_PRESENT = 0,
+
+  // At least one of 'name', 'filename' or 'filenae*' attributes were valid and
+  // yielded a non-empty filename.
+  CONTENT_DISPOSITION_IS_VALID,
+
+  // The following enum values correspond to
+  // net::HttpContentDisposition::ParseResult.
+  CONTENT_DISPOSITION_HAS_DISPOSITION_TYPE,
+  CONTENT_DISPOSITION_HAS_UNKNOWN_TYPE,
+  CONTENT_DISPOSITION_HAS_NAME,
+  CONTENT_DISPOSITION_HAS_FILENAME,
+  CONTENT_DISPOSITION_HAS_EXT_FILENAME,
+  CONTENT_DISPOSITION_HAS_NON_ASCII_STRINGS,
+  CONTENT_DISPOSITION_HAS_PERCENT_ENCODED_STRINGS,
+  CONTENT_DISPOSITION_HAS_RFC2047_ENCODED_STRINGS,
+
+  // Only have the 'name' attribute is present.
+  CONTENT_DISPOSITION_HAS_NAME_ONLY,
+
+  CONTENT_DISPOSITION_LAST_ENTRY
+};
+
+void RecordContentDispositionCount(ContentDispositionCountTypes type,
+                                   bool record) {
+  if (!record)
+    return;
+  UMA_HISTOGRAM_ENUMERATION(
+      "Download.ContentDisposition", type, CONTENT_DISPOSITION_LAST_ENTRY);
+}
+
+void RecordContentDispositionCountFlag(
+    ContentDispositionCountTypes type,
+    int flags_to_test,
+    net::HttpContentDisposition::ParseResultFlags flag) {
+  RecordContentDispositionCount(type, (flags_to_test & flag) == flag);
+}
+
+} // namespace
+
 void RecordDownloadCount(DownloadCountTypes type) {
   UMA_HISTOGRAM_ENUMERATION(
       "Download.Counts", type, DOWNLOAD_COUNT_TYPES_LAST_ENTRY);
@@ -252,6 +301,53 @@ void RecordDownloadMimeType(const std::string& mime_type_string) {
                             DOWNLOAD_CONTENT_MAX);
 }
 
+void RecordDownloadContentDisposition(
+    const std::string& content_disposition_string) {
+  if (content_disposition_string.empty())
+    return;
+  net::HttpContentDisposition content_disposition(
+      content_disposition_string, "");
+  int result = content_disposition.parse_result_flags();
+
+  bool is_valid = !content_disposition.filename().empty();
+  RecordContentDispositionCount(CONTENT_DISPOSITION_HEADER_PRESENT, true);
+  RecordContentDispositionCount(CONTENT_DISPOSITION_IS_VALID, is_valid);
+  if (!is_valid)
+    return;
+
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_DISPOSITION_TYPE, result,
+      net::HttpContentDisposition::HAS_DISPOSITION_TYPE);
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_UNKNOWN_TYPE, result,
+      net::HttpContentDisposition::HAS_UNKNOWN_DISPOSITION_TYPE);
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_NAME, result,
+      net::HttpContentDisposition::HAS_NAME);
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_FILENAME, result,
+      net::HttpContentDisposition::HAS_FILENAME);
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_EXT_FILENAME, result,
+      net::HttpContentDisposition::HAS_EXT_FILENAME);
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_NON_ASCII_STRINGS, result,
+      net::HttpContentDisposition::HAS_NON_ASCII_STRINGS);
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_PERCENT_ENCODED_STRINGS, result,
+      net::HttpContentDisposition::HAS_PERCENT_ENCODED_STRINGS);
+  RecordContentDispositionCountFlag(
+      CONTENT_DISPOSITION_HAS_RFC2047_ENCODED_STRINGS, result,
+      net::HttpContentDisposition::HAS_RFC2047_ENCODED_STRINGS);
+
+  RecordContentDispositionCount(
+      CONTENT_DISPOSITION_HAS_NAME_ONLY,
+      (result & (net::HttpContentDisposition::HAS_NAME |
+                 net::HttpContentDisposition::HAS_FILENAME |
+                 net::HttpContentDisposition::HAS_EXT_FILENAME)) ==
+      net::HttpContentDisposition::HAS_NAME);
+}
+
 void RecordFileThreadReceiveBuffers(size_t num_buffers) {
     UMA_HISTOGRAM_CUSTOM_COUNTS(
       "Download.FileThreadReceiveBuffers", num_buffers, 1,