diff options
Diffstat (limited to 'chromium/third_party/blink/public/common/frame/user_activation_state.h')
| -rw-r--r-- | chromium/third_party/blink/public/common/frame/user_activation_state.h | 91 |
1 files changed, 84 insertions, 7 deletions
diff --git a/chromium/third_party/blink/public/common/frame/user_activation_state.h b/chromium/third_party/blink/public/common/frame/user_activation_state.h index 6d0558e1b50..cf1f6dc933f 100644 --- a/chromium/third_party/blink/public/common/frame/user_activation_state.h +++ b/chromium/third_party/blink/public/common/frame/user_activation_state.h @@ -12,11 +12,79 @@ namespace blink { // This class represents the user activation state of a frame. It maintains two // bits of information: whether this frame has ever seen an activation in its -// lifetime, and whether this frame has a current activation that was neither -// expired nor consumed. +// lifetime (the sticky bit), and whether this frame has a current activation +// that is neither expired nor consumed (the transient bit). See User +// Activation v2 (UAv2) links below for more info. // -// This provides a simple alternative to current user gesture tracking code -// based on UserGestureIndicator and UserGestureToken. +// +// Tracking User Activation across the Frame Tree +// ============================================== +// +// This state changes in three ways: activation (of both bits) through user +// input notifications, and deactivation (of transient bit only) through expiry +// and consumption. +// +// - A notification update at a frame activates all ancestor frames (sets both +// bits to true). Also see "Same-origin Visibility" below. +// +// - A consumption call deactivates the transient bits in the whole frame tree. +// This exhaustive consumption guarantees that a malicious subframe can't embed +// sub-subframes in a way that could allow multiple consumptions per user +// activation. +// +// - After a certain time limit (few seconds), the transient bit is deactivated. +// (Internally, the class doens't store the transient bit, but stores the bit's +// expiry time instead.) +// +// +// Same-origin Visibility of User Activation +// ========================================= +// +// We launched UAv2 with a relaxed visibility model that a user activation is +// visible to all same-origin frames (w.r.t. the originally-activated frame), in +// addition to the ancestor frames as per UAv2. We will remove this relaxation +// after implementing a mechanism for activation transfer +// (https://crbug.com/928838). +// +// Details: Before UAv2, user activation was visible to all same-process frames +// and no cross-process frames (undocumented). The ancestor-only restriction +// with UAv2 caused a few breakages because of reliance on the old assumption, +// see the Type=Bug-Regression bugs blocking the above bug. Once we have a +// workaround for those broken cases (most likely through a postMessage +// transfer), we will go back to the ancestor-only visibility model. +// +// +// State Replication in Browser and Renderers +// ========================================== +// +// The user activation state is replicated in the browser process (in +// |FrameTreeNode|) and in the renderer processes (in |LocalFrame| and +// |RemoteFrame|). The replicated states across the browser and renderer +// processes are kept in sync as follows: +// +// [A] Consumption of activation state for popups starts in the frame tree of +// the browser process and propagate to the renderer trees through direct IPCs +// (one IPC sent to each renderer). +// +// [B] Consumption calls from JS/blink side (e.g. video picture-in-picture) +// update the originating renderer's local frame tree and send an IPC to the +// browser; the browser updates its frame tree and sends IPCs to all other +// renderers each of which then updates its local frame tree. +// +// [B'] Notification updates on user inputs is like [B] (renderer first). These +// should really be like [A] (browser first), see https://crbug.com/848778. +// +// [C] Expiration of an active state is tracked independently in each process. +// +// +// More Info +// ========= +// +// - UAv2 explainer: https://mustaqahmed.github.io/user-activation-v2 +// - Main design: +// https://docs.google.com/a/chromium.org/document/d/1erpl1yqJlc1pH0QvVVmi1s3WzqQLsEXTLLh6VuYp228 +// - Browser-side replication for OOPIFs: +// https://docs.google.com/document/d/1XL3vCedkqL65ueaGVD-kfB5RnnrnTaxLc7kmU91oerg class BLINK_COMMON_EXPORT UserActivationState { public: void Activate(); @@ -28,16 +96,25 @@ class BLINK_COMMON_EXPORT UserActivationState { // Returns the transient activation state, which is |true| if the frame has // recently been activated and the transient state hasn't been consumed yet. - bool IsActive(); + bool IsActive() const; // Consumes the transient activation state if available, and returns |true| if // successfully consumed. bool ConsumeIfActive(); + // Transfers user activation state from |other| into |this|: + // - The sticky bit in |this| gets set if the bit in |other| is set. + // - The transient expiry time in |this| becomes the max of the expiry times + // in |this| and |other|. + // - The state in |other| is cleared. + void TransferFrom(UserActivationState& other); + private: + void ActivateTransientState(); + void DeactivateTransientState(); + bool has_been_active_ = false; - bool is_active_ = false; - base::TimeTicks activation_timestamp_; + base::TimeTicks transient_state_expiry_time_; }; } // namespace blink |