Proof of concept implementation of context based history filtering.

components/history/core/browser/url_row.h

Index: components/history/core/browser/url_row.h
diff --git a/components/history/core/browser/url_row.h b/components/history/core/browser/url_row.h
index f7c956b60071121a2cf1ecbdbfdac2ef0fbd95c2..1d4d28069ee05942f99f82b32db5dacd39c7ab73 100644
--- a/components/history/core/browser/url_row.h
+++ b/components/history/core/browser/url_row.h
@@ -27,6 +27,15 @@ typedef int64 URLID;
 // Second, there is a problem copying. If you make a copy of this structure
 // (as we allow since we put this into vectors in various places) then the
 // dirty bits will not be in sync for these copies.
+
+enum HistoryContext {
+  CONTEXT_NONE = 0, // No distinctive context available.
+  CONTEXT_COPY = 1, // User copied some content.
+  CONTEXT_SAVE_IMAGE = 2, // User saved any image.
+  CONTEXT_PRINT = 3, // User printed the content.
+  CONTEXT_MEDIA_PLAY = 4, // User shares any link.
+};
+
 class URLRow {
  public:
   URLRow();
@@ -99,6 +108,13 @@ class URLRow {
     hidden_ = hidden;
   }
 
+  HistoryContext context() const {
+    return context_;
+  }
+  void set_context(HistoryContext context) {
+    context_ = context;
+  }
+
   // Helper functor that determines if an URLRow refers to a given URL.
   class URLRowHasURL {
    public:
@@ -153,6 +169,7 @@ class URLRow {
   // is usually for subframes.
   bool hidden_;
 
+  HistoryContext context_;
   // We support the implicit copy constuctor and operator=.
 };
 typedef std::vector<URLRow> URLRows;