Adds Server Previews protocol UMA plus UMA for not accepting previews

components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
index 465ec6cf16bb31ab35a54fef218ea4f3707994cb..645ff67fb4261f6a645508c778e330a2d48f8080 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
@@ -43,6 +43,20 @@ namespace data_reduction_proxy {
 
 namespace {
 
+// Values of the UMA DataReductionProxy.Protocol.AcceptTransform histogram
+// defined in metrics/histograms/histograms.xml. This enum must remain
+// synchronized with DataReductionProxyProtocolAcceptTransformEvent in
+// tools/metrics/histograms/enums.xml.
+enum AcceptTransformEvent {
+  ACCEPT_LITE_PAGE_SENT = 0,
+  TRANSFORM_LITE_PAGE_RECEIVED = 1,
+  POLICY_EMPTY_IMAGE_RECEIVED = 2,
+  ACCEPT_EMPTY_IMAGE_SENT = 3,
+  TRANSFORM_EMPTY_IMAGE_RECEIVED = 4,
+  ACCEPT_COMPRESSED_VIDEO_SENT = 5,
+  ACCEPT_TRANSFORM_EVENT_BOUNDARY
+};
+
 // Records the occurrence of |sample| in |name| histogram. UMA macros are not
 // used because the |name| is not static.
 void RecordNewContentLengthHistogram(const std::string& name, int64_t sample) {
@@ -165,6 +179,53 @@ void RecordContentLengthHistograms(bool lofi_low_header_added,
                           received_content_length);
 }
 
+void RecordAcceptTransformEvent(AcceptTransformEvent event) {
+  UMA_HISTOGRAM_ENUMERATION("DataReductionProxy.Protocol.AcceptTransform",
+                            event, ACCEPT_TRANSFORM_EVENT_BOUNDARY);
+}
+
+void RecordAcceptTransformSentUMA(
+    const net::HttpRequestHeaders& request_headers) {
+  std::string accept_transform_header_value;
+  if (request_headers.GetHeader(chrome_proxy_accept_transform_header(),
+                                &accept_transform_header_value)) {
+    if (std::string::npos !=
+        accept_transform_header_value.find(lite_page_directive())) {

[bengr, 2017/06/26 18:11:47]

This is a very brittle way of finding directives in the CP header. We should
have a method that parses the CP header into an object.

[dougarnett, 2017/06/26 21:19:16]

Added methods to parse headers into a single TransformType and now calling them
from these Record methods.

+      RecordAcceptTransformEvent(ACCEPT_LITE_PAGE_SENT);
+    } else if (std::string::npos !=
+               accept_transform_header_value.find(empty_image_directive())) {
+      RecordAcceptTransformEvent(ACCEPT_EMPTY_IMAGE_SENT);
+    } else if (std::string::npos != accept_transform_header_value.find(
+                                        compressed_video_directive())) {
+      RecordAcceptTransformEvent(ACCEPT_COMPRESSED_VIDEO_SENT);
+    } else {
+      NOTREACHED() << "Unexpected accept transform: "
+                   << accept_transform_header_value;
+    }
+  }
+}
+
+void RecordAcceptTransformReceivedUMA(const net::URLRequest& request) {
+  net::HttpResponseHeaders* response_headers = request.response_headers();
+  if (!response_headers)
+    return;
+
+  if (IsLitePagePreview(*response_headers)) {
+    RecordAcceptTransformEvent(TRANSFORM_LITE_PAGE_RECEIVED);
+  } else if (IsEmptyImagePreview(*response_headers)) {
+    RecordAcceptTransformEvent(TRANSFORM_EMPTY_IMAGE_RECEIVED);
+  } else {
+    std::string chrome_proxy_header_value;
+    if (response_headers->GetNormalizedHeader(chrome_proxy_header(),
+                                              &chrome_proxy_header_value) &&
+        std::string::npos !=
+            chrome_proxy_header_value.find(
+                chrome_proxy_page_policies_empty_image_directive())) {
+      RecordAcceptTransformEvent(POLICY_EMPTY_IMAGE_RECEIVED);
+    }
+  }
+}
+
 // Verifies that the chrome proxy related request headers are set correctly.
 // |via_chrome_proxy| is true if the request is being fetched via Chrome Data
 // Saver proxy.
@@ -373,6 +434,7 @@ void DataReductionProxyNetworkDelegate::OnBeforeSendHeadersInternal(
   data_reduction_proxy_request_options_->AddRequestHeader(headers, page_id);
 
   VerifyHttpRequestHeaders(true, *headers);
+  RecordAcceptTransformSentUMA(*headers);
 }
 
 void DataReductionProxyNetworkDelegate::OnBeforeRedirectInternal(
@@ -456,6 +518,7 @@ void DataReductionProxyNetworkDelegate::OnCompletedInternal(
   CalculateAndRecordDataUsage(*request, request_type);
 
   RecordContentLength(*request, request_type, original_content_length);
+  RecordAcceptTransformReceivedUMA(*request);
 }
 
 void DataReductionProxyNetworkDelegate::OnHeadersReceivedInternal(