diff --git a/libcef/browser/browser_context_proxy.cc b/libcef/browser/browser_context_proxy.cc
index ca5749006..c1772becf 100644
--- a/libcef/browser/browser_context_proxy.cc
+++ b/libcef/browser/browser_context_proxy.cc
@@ -10,8 +10,28 @@
 #include "libcef/browser/url_request_context_getter_proxy.h"
 
 #include "base/logging.h"
+#include "components/guest_view/common/guest_view_constants.h"
+#include "content/browser/streams/stream_context.h"
 #include "content/public/browser/storage_partition.h"
 
+namespace {
+
+bool ShouldProxyUserData(const void* key) {
+  // If this value is not proxied the blob data fails to load for the PDF
+  // extension.
+  if (key == content::StreamContext::GetUserDataKey())
+    return true;
+
+  // If this value is not proxied then CefBrowserContextImpl::GetGuestManager()
+  // returns NULL.
+  if (key == guest_view::kGuestViewManagerKeyName)
+    return true;
+
+  return false;
+}
+
+}  // namespace
+
 CefBrowserContextProxy::CefBrowserContextProxy(
     CefRefPtr<CefRequestContextHandler> handler,
     scoped_refptr<CefBrowserContextImpl> parent)
@@ -26,6 +46,27 @@ CefBrowserContextProxy::~CefBrowserContextProxy() {
   parent_->RemoveProxy(this);
 }
 
+base::SupportsUserData::Data*
+    CefBrowserContextProxy::GetUserData(const void* key) const {
+  if (ShouldProxyUserData(key))
+    return parent_->GetUserData(key);
+  return BrowserContext::GetUserData(key);
+}
+
+void CefBrowserContextProxy::SetUserData(const void* key, Data* data) {
+  if (ShouldProxyUserData(key))
+    parent_->SetUserData(key, data);
+  else
+    BrowserContext::SetUserData(key, data);
+}
+
+void CefBrowserContextProxy::RemoveUserData(const void* key) {
+  if (ShouldProxyUserData(key))
+    parent_->RemoveUserData(key);
+  else
+    BrowserContext::RemoveUserData(key);
+}
+
 base::FilePath CefBrowserContextProxy::GetPath() const {
   return parent_->GetPath();
 }
diff --git a/libcef/browser/browser_context_proxy.h b/libcef/browser/browser_context_proxy.h
index 51488ff64..fea07432f 100644
--- a/libcef/browser/browser_context_proxy.h
+++ b/libcef/browser/browser_context_proxy.h
@@ -29,6 +29,11 @@ class CefBrowserContextProxy : public CefBrowserContext {
   CefBrowserContextProxy(CefRefPtr<CefRequestContextHandler> handler,
                          scoped_refptr<CefBrowserContextImpl> parent);
 
+  // SupportsUserData methods.
+  Data* GetUserData(const void* key) const override;
+  void SetUserData(const void* key, Data* data) override;
+  void RemoveUserData(const void* key) override;
+
   // BrowserContext methods.
   base::FilePath GetPath() const override;
   scoped_ptr<content::ZoomLevelDelegate> CreateZoomLevelDelegate(
diff --git a/patch/patch.cfg b/patch/patch.cfg
index 2dd4be043..6b8a60079 100644
--- a/patch/patch.cfg
+++ b/patch/patch.cfg
@@ -190,4 +190,16 @@ patches = [
     'name': 'browser_frame_host_guest_1687',
     'path': '../content/browser/frame_host/',
   },
+  {
+    # Fix loading of the PDF extension with proxy BrowserContext.
+    # https://bitbucket.org/chromiumembedded/cef/issues/1710
+    'name': 'stream_context_1710',
+    'path': '../content/browser/streams/',
+  },
+  {
+    # Fix loading of the PDF extension with proxy BrowserContext.
+    # https://bitbucket.org/chromiumembedded/cef/issues/1710
+    'name': 'supports_user_data_1710',
+    'path': '../base/',
+  },
 ]
diff --git a/patch/patches/stream_context_1710.patch b/patch/patches/stream_context_1710.patch
new file mode 100644
index 000000000..3aff4098c
--- /dev/null
+++ b/patch/patches/stream_context_1710.patch
@@ -0,0 +1,27 @@
+diff --git stream_context.cc stream_context.cc
+index e338396..150cde5 100644
+--- stream_context.cc
++++ stream_context.cc
+@@ -19,6 +19,10 @@ namespace content {
+ 
+ StreamContext::StreamContext() {}
+ 
++const void* StreamContext::GetUserDataKey() {
++  return kStreamContextKeyName;
++}
++
+ StreamContext* StreamContext::GetFor(BrowserContext* context) {
+   if (!context->GetUserData(kStreamContextKeyName)) {
+     scoped_refptr<StreamContext> stream = new StreamContext();
+diff --git stream_context.h stream_context.h
+index ad8f65c..60310db 100644
+--- stream_context.h
++++ stream_context.h
+@@ -28,6 +28,7 @@ class StreamContext
+  public:
+   StreamContext();
+ 
++  CONTENT_EXPORT static const void* GetUserDataKey();
+   CONTENT_EXPORT static StreamContext* GetFor(BrowserContext* browser_context);
+ 
+   void InitializeOnIOThread();
diff --git a/patch/patches/supports_user_data_1710.patch b/patch/patches/supports_user_data_1710.patch
new file mode 100644
index 000000000..e336293b8
--- /dev/null
+++ b/patch/patches/supports_user_data_1710.patch
@@ -0,0 +1,17 @@
+diff --git supports_user_data.h supports_user_data.h
+index 711ee7d..cf38fc0 100644
+--- supports_user_data.h
++++ supports_user_data.h
+@@ -32,9 +32,9 @@ class BASE_EXPORT SupportsUserData {
+   // Multiple user data values can be stored under different keys.
+   // This object will TAKE OWNERSHIP of the given data pointer, and will
+   // delete the object if it is changed or the object is destroyed.
+-  Data* GetUserData(const void* key) const;
+-  void SetUserData(const void* key, Data* data);
+-  void RemoveUserData(const void* key);
++  virtual Data* GetUserData(const void* key) const;
++  virtual void SetUserData(const void* key, Data* data);
++  virtual void RemoveUserData(const void* key);
+ 
+   // SupportsUserData is not thread-safe, and on debug build will assert it is
+   // only used on one thread. Calling this method allows the caller to hand